You are on page 1of 118

ECONOMIC AND SECTOR WORK

CARBON SEQUESTRATION
IN AGRICULTURAL SOILS

M AY 2 0 1 2

REPORT NUMBER: 67395-GLB

ECONOMIC AND SECTOR WORK

CARBON SEQUESTRATION
IN AGRICULTURAL SOILS

REPORT NO. 67395-GLB

ARD

AGRICULTURE AND
RURAL DEVELOPMENT

© 2012 International Bank for Reconstruction and Development/International Development Association or
The World Bank
1818 H Street NW
Washington DC 20433
Telephone: 202-473-1000
Internet: www.worldbank.org
This volume is a product of the staff of the International Bank for Reconstruction and Development/ The World Bank.
The findings, interpretations, and conclusions expressed in this paper do not necessarily reflect the views of the Executive
Directors of The World Bank or the governments they represent.
The World Bank does not guarantee the accuracy of the data included in this work. The boundaries, colors, denominations,
and other information shown on any map in this work do not imply any judgment on the part of The World Bank concerning
the legal status of any territory or the endorsement or acceptance of such boundaries.
Rights and Permissions
The material in this work is subject to copyright. Because The World Bank encourages dissemination of its knowledge, this
work may be reproduced, in whole or in part, for noncommercial purposes as long as full attribution to this work is given.
Any queries on rights and licenses, including subsidiary rights, should be addressed to the Office of the Publisher,
The World Bank, 1818 H Street NW, Washington, DC 20433, USA; fax: 202-522-2422; e-mail: pubrights@worldbank.org.
Cover Photos: Scott Wallace, Tran Thi Hoa, Curt Carnemark, Ami Vitale, and Ray Witlin.

CONTENTS

TABLE OF CONTENTS

List of Figures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v
List of Photos . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vi
List of Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vii
List of Boxes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . viii
Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ix
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xi
Abbreviations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xiii
Executive Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xv
Chapter 1: Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.1: Food Security Under a Changing Climate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2: Carbon Benefits Through Climate-Smart Agriculture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.3: Objectives and Scope of the Report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Chapter 2: Soil Organic Carbon Dynamics and Assessment Methods . . . . . . . . . . . . . . . . . . 5
2.1: Soil Organic Carbon Dynamics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.2: Carbon Assessment for Land Management Projects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
2.3: Techniques of Soil Carbon Assessment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
2.4: Carbon Assessment in The World Bank’s Sustainable Land Management Portfolio . . . . . . . . . . . . . 17

Chapter 3: Meta-Analyses of Soil Carbon Sequestration . . . . . . . . . . . . . . . . . . . . . . . . . . 19
3.1: Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
3.2: Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
3.3: Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Chapter 4: Ecosystem Simulation Modeling of Soil Carbon Sequestration . . . . . . . . . . . . . . 43
4.1: Model Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
4.2: Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

Chapter 5: Economics of Soil Carbon Sequestration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
5.1: Marginal Abatement Costs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
5.2: Trade-Offs in Soil Carbon Sequestration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
5.3: Implications of the Trade-Offs in Land-Use Decisions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
5.4: Sustainable Land Management Adoption Barriers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
5.5: Policy Options for Soil Carbon Sequestration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

EC O N O M I C A N D S E CT OR WORK

III

IV

C ONTENTS

Appendix A: The Farming Practice Effect, Number of Estimates, and Features in Land
Management Practices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
Appendix B: General Scenario Assumptions and Application for World Regions . . . . . . . . . . 67
B.1: Baseline Scenario . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
B.2: Global Mitigation Scenarios . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
B.3: Application to World Regions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
B.4: Detailed Modeling for Africa . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70

Appendix C: Global Crop Yields (T ha −1 yr−1) Grouped into 25th, 50th, and 75th Percentile
Bins Corresponding to Low, Medium, and High . . . . . . . . . . . . . . . . . . . . . . . 75
Appendix D: Uncertainty Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
Appendix E: Assumptions for Deriving the Applicable Mitigation Area for the Land
Management Practices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
E.1: Africa . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83

CARBON SEQUESTRATION IN AGRICULTURAL SOILS

LI S T O F F I G U R E S

LIST OF FIGURES

Figure E1: Abatement Rates of the Land Management Practices (t CO2e Per Hectare Per Year) . . . . . . . . . .xxii
Figure E2: Trade-Offs Between Profitability and Carbon Sequestration of Sustainable Land Management
Technologies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .xxv
Figure E3: Relationship Between Private Benefits and Public Costs . . . . . . . . . . . . . . . . . . . . . . . xxvi
Figure 1.1: Contribution of Different Sectors to Greenhouse Gas (GHG) Emissions . . . . . . . . . . . . . . . . . 1
Figure 1.2: Proportion of Agricultural Land Derived from Different Land Covers in the Tropics, 1980–2000 . . . . . 2
Figure 2.1: Carbon Stocks in Biomass and Soils. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Figure 2.2: Global Soil Regions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Figure 2.3: Factors Affecting Soil Carbon Sequestration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Figure 3.1: Geographical Distribution of Carbon Sequestration Estimates . . . . . . . . . . . . . . . . . . . . . 21
Figure 3.2: Soil Carbon Sequestration and Precipitation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Figure 3.3: Soil Carbon Sequestration and Temperature. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Figure 3.4: Soil Carbon Sequestration and Soil Order . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Figure 3.5: Soil Carbon Sequestration and Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Figure 3.6: Soil Carbon Sequestration and Application Levels of Nitrogen Fertilizer
(Means and 95 Percent Confidence Intervals, n = 285) . . . . . . . . . . . . . . . . . . . . . . . . . 26
Figure 3.7: Soil Carbon Sequestration and Fertilizer Combinations (Means and 95 Percent Confidence
Intervals, n = 285) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Figure 3.8: Mean Soil Carbon Sequestration and Levels of Residue Returned . . . . . . . . . . . . . . . . . . . 30
Figure 3.9: Classification of Tillage Systems Based on Crop Residue Management . . . . . . . . . . . . . . . . 31
Figure 3.10: Mean Soil Carbon Sequestration and Cropping Intensity . . . . . . . . . . . . . . . . . . . . . . . 33
Figure 3.11: Carbon Dioxide Abatement Rates of the Land Management Practices . . . . . . . . . . . . . . . . 39
Figure 4.1: Representation of the RothC Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Figure 4.2: The 12 Strata Used for Ecosystem Simulation Modeling . . . . . . . . . . . . . . . . . . . . . . . . 45
Figure 4.3: Africa Agroecological Zone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
Figure 4.4: A Screen Shot of the Soil Carbon Internet Database . . . . . . . . . . . . . . . . . . . . . . . . . . 47
Figure 4.5: Cumulative Soil Carbon Loss by 2030 Assuming 15 Percent Residue Retention (t ha−1)
under Different Cropping Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
EC O N O M I C A N D S E CT OR WORK

V

. . . .2: Crop Residue Management in Irrigated Fields in Indonesia . . . . . . . . .3: Water Management in a Field in India . . . . . . . . 54 Figure 5. . . . . . . . . . . . . . . . . . . . . . . . .3: Trade-Offs Between Profitability and Carbon Sequestration of Sustainable Land Management Technologies in Africa . . . . . . . . . . . . . . 71 LIST OF PHOTOS Photo E. . . . .1: The Private Marginal Abatement Cost Curves. . . . . . . 49 Figure 5. . . .1: Terracing and Landscape Management in Bhutan . . . . . . . . . . . . . . . . . 40 Photo 5. . . . . . . . . . . . . . . . . . . . . . . . . . The Biomass Is Smaller Compared to that of Agroforestry Systems. . . . . . . . . . . . . . . . . . . 34 Photo 3. The Biomass Is Smaller Compared to that of Agroforestry Systems. . . . . . . . . . . . . . . . . . . . . . . . . .VI LIST O F FIGUR ES Figure 4. . . 56 Figure B. . . . . . . .1: Crop Residue Management in Irrigated Fields in Indonesia .5: Crop Harvesting in Mali. . .2: Total Private Benefits (Blue) and Public Costs (Red) of Land Management Practices (US$. . . .2: Water Management in a Field in India . . . . . . . . . . . . . . Billion) for the B1 Scenario . . . . . . . .4: Relationship Between Private Benefits and Public Costs in Africa . . .xxv Photo 3. . . . . . . . . . . . .1: FAO Land-Use Map . . . . . . . . . . .4: Crop Harvesting in Mali. . 33 Photo 3. 52 Figure 5. . . . . . . . . . xxiii Photo E. . . . . .4: Maize Growing under Faidherbia Albida Trees in Tanzania . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57 CARBON SEQUESTRATION IN AGRICULTURAL SOILS . . . . . .6: Predicted Cumulative C Sequestration for Different Land Management Practices by 2030 . . . . . . . . . . . xxiv Photo E. . . . . .1: Terracing and Landscape Management in Bhutan . . . . . . . . . . . . . . . .xvii Photo E. . . . . . . . . 55 Figure 5. 29 Photo 3.3: Maize Growing under Faidherbia Albida Trees in Tanzania . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xx Photo E. . . . . . . . . . . . . . . . . . . .

. . . 35 Table 3. . . . . . . . . . . 16 Table 2. . . 7 Table 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6: Water Management and Soil Carbon Sequestration Rates (kg C ha−1 yr−1) . . . . . . . . . . . . . . . . . 32 Table 3. . . . . . . . . .4: Tillage. . . 8 Table 2. . . . . . . 27 Table 3. . . . . . . . . . . . . 6 Table 2. . . . . . . . . . . . . . . . . . . . . . 28 Table 3. . . . . . . . . . . . . . . . . . . . . .2: Global Carbon Budget (Gt C) . . . . . . . . .4: Soil Carbon Pool up to 1-Meter Deep for Soil Orders of the World’s Ice-Free Land Surface . . . . . 14 Table 2. 16 Table 3. . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Table 1. . . . . . . . . . . . . . . . . 14 Table 2. . . .3: Forms of Carbon in the Soil . .LI S T O F TA B L E S LIST OF TABLES Table E1: Carbon Stocks in Vegetation and Top 1 Meter of Soils of World Biomes . . . . . . . . . . . . . . . . . . . . . . . .1: Practices That Sequester Carbon in Forest. . . . .5: Crop Rotation and Soil Sequestration Rates (kg C ha−1 yr−1) . . . . . 15 Table 2. . .1: Improvement in Crop Yields Per Ton of Carbon in the Root Zone . . . . . Private Benefits. . . . . Crop Residue Management. . . . . . . . . . . . . . . . . . . . 13 Table 2. . 10 Table 2. . . . . . . . . . . . . . .5: Estimate of Erosion-Induced Carbon Emission . . . . . . . . .7: Agroforestry and Soil Carbon Sequestration Rates (kg C ha−1 yr−1) . . . . . . . . . . . . . . . . . . . . . .2: Estimated Increase in Grain Crop Production From Land Management Technologies That Sequester Soil Carbon (Million Tons Per Year) . . . . . . . . . .6: Comparison of Carbon Assessment for Carbon Mitigation and Noncarbon Mitigation Projects . . . and Public Costs of the Land Management Technologies by 2030 . . .xvii Table E2: Estimates of Erosion-Induced Carbon Emission Across World Regions. . . .3: Relative Importance of the Four Domains of Integration on Crop-Livestock Interaction . . . . . . . . . 6 Table 2. . . . . . . and Cropland . . . . . . . 36 EC O N O M I C A N D S E CT OR WORK V II . . . . . . . .10: Components of Soil Carbon Monitoring at the Regional Scale . . . . . .9: Comparative Features of Some Carbon Estimation Models . . . . . . 19 Table 3. . . . . . . . . . . . . . . . . . . . . Grassland. . . . . . . . . .11: Carbon Accounting Systems and Tools . . . . . . . . . . . . . . . . . . . . . . . . . xxviii Table 1. . . . . . . . . . . . . . . . . . . . . .2: Nutrient Management and Soil Carbon Sequestration Rates (kg C ha−1 yr−1) . .8: Land-Use Changes and Soil Carbon Sequestration Rates (kg C ha−1 yr−1). . . . . . . . . . . and Soil Carbon Sequestration Rates (kg C ha−1 yr−1) . .7: Direct and Indirect Methods of Soil Carbon Assessment. . . . . . . . . . . . . . . . . 3 Table 2. .1: Carbon Stocks in Vegetation and Top 1 Meter of Soils of World Biomes . xviii Table E3: Technical Mitigation Potential. . . . . . . . . . . . . . . . 34 Table 3. . . 29 Table 3. . . . . .8: Characteristics of Emerging In Situ Methods of Soil Carbon Analytical Techniques . . . . . . . xxvii Table E4: Relative Importance of Different Factors for Adopting Improved Land Management Practices . . . . . . . . .

. . . . . . . . . . . . . . . 59 CARBON SEQUESTRATION IN AGRICULTURAL SOILS . . . . . . 37 Table 3. . . . . . . . . 9 Box 2. . . . . . . . . . . . 60 Table 5. . . . . . . . . . . . . . . . . . . . . . . . . . . .2: Modeled Cumulative Soil Carbon Sequestration Potential by 2030 (Mt C) under Different Land Management Practices . . . . . . . . . . . . . . . . . . . . . . . . .10: Soil Amendments and Soil Carbon Sequestration Rates (kg C ha−1 yr−1) . . .1: Risk-Related Barriers to Adoption of Soil Carbon Sequestration Activities . . . . . 11 Box 5.5: C Inputs for Different Agroforestry Systems . . . . . . . . . . . .2: Public Costs of Different Technologies Per Ton of Carbon Dioxide Sequestered. 60 Table B. . . . . . . . . 69 Table B. . . . . . . . . . . . . . 72 Table B. .1: Spatial Datasets Used in the Study . . . . . 82 Table E. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 Table 4. . 70 Table B. . . .2: Estimated Cropland and Grassland Area by 2030 (Million Hectare). . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 Table 5. . . . . . . . 84 LIST OF BOXES Box 2. . . . . . . . . .1: Estimated Cropland Area in the 2000s . . Private Benefits. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 Table 5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4: C Inputs for Different Green Manure/Cover Crop Systems. . . . . . . 53 Table 5. . . . . . . . . . . . . . . . . . . . . . . . 44 Table 4. . . . . 69 Table B. . . . . . .5: Interventions for Facilitating Increased Input Use . . .1: Brief Description of Soil Orders .2: Sustainable Land Management Practices Reverse Soil Carbon Loss in Java. . . . 83 Table E. . . . 55 Table 5. . . . . . . 73 Table D. . . . and Public Costs of the Land Management Technologies by 2030 . . . . . . . . . . . . .3: Manure C Inputs for the AEZs in Africa Based on FAOSTAT . . . . . . . .4: Relative Importance of Different Factors for Adopting Improved Land Management Practices . . . . . . .9: Summary of Observed Rates of Soil Carbon Sequestration (kg C ha−1 yr−1) as a Result of Land-Use Changes and Other Practices Relevant to Livestock Management . . . . . . .1: Private Savings of Different Technologies Per Ton of Carbon Dioxide Sequestered . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2: Agricultural Systems and Mitigation Scenario in Central America . .VIII LIS T OF TA B LES Table 3. . . . . . . . . . . . . . . . . . . .1: Agricultural Systems and Mitigation Scenario in South America . . . . . . . . . . . . . . . . .1: Uncertainty Analyses Using Random Samples from the Mitigation Scenarios. .3: Technical Mitigation Potential.

Too often the relationship between these roles is viewed as a series of painful trade-offs. The growing consensus on the need for a climate-smart agriculture emerged largely out of international awareness of the sector’s negative impacts—its ecological footprint. we understand not only the significance that climate has for agriculture. As this document will discuss. and for the food security of vulnerable populations in particular. and the principal driver behind deforestation worldwide. and in addition to their technical feasibility. Higher carbon content enables the soil to make more water and nutrients available to support crop growth. It also grew out of the recognition that conventional forms of agricultural production are often unsustainable and deplete or “mine” the natural resources on which production relies over time. Yet the same carbon that is sequestered through sustainable practices makes those practices more productive. Some 30 percent of global greenhouse gas emissions are attributable to agriculture and deforestation driven by the expansion of crop and livestock production for food. Production relies directly on soil. but it is not its only priority. The agriculture systems that supply this food play a pivotal role in these countries’ economies. This trend is projected to intensify in the coming decades and have serious ramifications for global food security. and that leads to higher profit margins for producers. Agriculture is the world’s leading source of methane and nitrous oxide emissions. More recently. Increasing productivity is agriculture’s most pressing priority. Today. more than ever before. fiber and fuel. its biomass and especially its soils also sequester carbon out of the atmosphere. with a growing understanding of the environmental services the sector can provide if production is well-managed. These technical elements of climate-smart agriculture are by now well understood. this perspective of agriculture as a source of greenhouse gas emissions and pollution has become more balanced. Agriculture employs up to two-thirds of their workforce and accounts for between 10 and 30 percent of their gross domestic product. and this role as a carbon sink and as a carbon store can be strategically optimized through proven farming techniques and methods that simultaneously reduce emissions. they can be highly productive and profitable. The carbon that is removed from the atmosphere and captured in soils and plant biomass is the same carbon that makes agricultural soils more fertile. EC O N O M I C A N D S E CT OR WORK IX . reducing both the need for fertilizer applications and susceptibility to land degradation. but also the enormous significance that agriculture has for the climate. Food production will need to effectively double in many developing countries by 2050 to feed a growing and increasingly urban global population. a substantial source of carbon emissions. Agricultural production operates under intensifying pressures. Perhaps the most important point conveyed in this document is that the dual roles of agriculture as a source of food security and as a source of environmental services converge in fundamental ways. While agriculture emits a large volume of greenhouse gases. and increases the resilience of farmland. The Intercontinental Panel on Climate Change (IPCC) indicates that carbon sequestration accounts for about 90 percent of global agricultural mitigation potential by 2030.PR E FA C E PREFACE Agriculture’s direct reliance on the natural resource base has always been a defining characteristic of the sector. And it also relies on the climate at the same time that its role in the global carbon cycle makes it a major contributing factor to climate change. this new and more sustainable pattern of agricultural development can make the sector an active agent in climate change mitigation at the same time that it improves and builds upon the sector’s capacity to adapt to the increasing temperatures and declining precipitation that are already reducing yields of grains and other primary crops in many parts of the vast semi-arid tropics where so many of the poorest reside. water. and a variety of biological processes.

It is our hope that this report moves that agenda forward by making the “triple win” of soil carbon sequestration for increased productivity. the adoption of these approaches still faces serious constraints in many developing countries. Among the most important of these constraints are the significant upfront expenditures that many of the newer techniques require. Mobilizing and targeting resources to overcome these constraints has been an important reason the World Bank became determined to get climate-smart agriculture more firmly onto the agenda of the international dialogue on climate change. In many of the developing countries in which these techniques would wield some of their most important benefits. improved climate resilience.X PR EFA C E While technical progress in the area of integrated “landscape” approaches to managing natural and economic resources has been very promising. and enhanced mitigation an integral part of that dialogue. Juergen Voegele Director Agriculture and Rural Development Department The World Bank CARBON SEQUESTRATION IN AGRICULTURAL SOILS . awareness of both the techniques and the benefits remain limited. In some settings there is limited capacity to implement them even when people are aware of them.

Tim Searchinger. Meine van Noordwijk. This report improves the knowledge base for scaling-up investments in land management technologies that sequester soil carbon for increased productivity under changing climate conditions. Shunalini Sarkar. Sarian Akibo-Betts. Yurie Tanimichi Hoberg. Louis Bockel. Marjory-Anne Bromhead. Ramon Yndriago. Matthias Seebauer. Johannes Woelcke. Cicely Spooner. John Idowu. EC O N O M I C A N D S E CT OR WORK XI . Ademola Braimoh wrote the report with meta-analyses and research support from Idowu Oladele. Varuna Somaweera. Dany Jones. Johannes Heister. Dipti Thapa. Many others provided inputs and support including Jurgen Voegele. The author is grateful for constructive comments and suggestions from the following peer reviewers: Erick Fernandes. Patricia del Valle Pérez. Maria Gabitan. Patrick Verkoijen. Gunnar Larson. Pai-Yei Whung. and Ijeoma Emenanjo. Katie McWilliams. and Andreas Wilkes. while Reza Firuzabadi. Christine Negra. and Katia Obst carried out the ecosystem simulation modeling. and Genalinda Gorospe. Fionna Douglas. Sarah Elizabeth Antos.ACK N O W L E D G ME NT S ACKNOWLEDGMENTS The preparation of this report was managed by the Agriculture and Rural Development (ARD) department. Louis Lebel. Michael Kane. Mark Cackler. Wilhelmus Janssen. and Alex Stoicof provided Geographical Information System and Information Technology support. Chuck Rice. Kaisa Antikainen. Ellysar Baroudy.

.

monitoring.ABB R E V I AT I O N S X III ABBREVIATIONS AEZ Agroecological Zone HUM humified organic matter BIO microbial biomass INS inelastic neutron scattering CBP Carbon Benefits Project IOM inert organic matter CSA climate-smart agriculture IPCC Intercontinental Panel on Climate Change DPM decomposable plant material LIBS laser-induced breakdown spectroscopy EX-ACT Ex Ante Appraisal Carbon-Balance Tool MAC marginal abatement cost FAOSTAT Food and Agriculture Organization of the United Nations MMV measurement. and verification NPP net primary productivity GEF Global Environment Facility RPM resistant plant material SALM Sustainable Agricultural Land Management SLM sustainable land management UNFCCC UN Framework Convention on Climate Change GHG greenhouse gas GIS geographical information system GPS global positioning system ha hectare EC O N O M I C A N D S E CT OR WORK .

.

Moreover. and Latin America. agriculture and the changes in land-use that are associated with it. and reducing the emissions that come from the agriculture sector are therefore triple imperatives that require alternative sets of practices. and reduce agriculture’s contribution to climate change by reducing GHG emissions and sequestering carbon.EX E C U T I V E S U MMARY EXECUTIVE SUMMARY Ensuring food security in a context of growing population and changing climate is arguably the principal challenge of our time. Increasing agricultural productivity. limit GHG concentrations in the atmosphere. food production must increase by more than 100 percent—it must effectively double. Carbon sequestration. projections indicate that global food production must increase by 70 percent by 2050. In many African countries. rising incomes and the increasing proportion of the global population living in urban areas are changing the composition of food demand in fundamental ways. enhancing its resilience to climate change. can help reverse soil fertility loss. The results EC O N O M I C A N D S E CT OR WORK XV . the process by which atmospheric carbon dioxide is taken up by plants through photosynthesis and stored as carbon in biomass and soils. The first was a review of soil carbon dynamics and assessment methods and a meta-analysis of soil carbon sequestration rates in Africa. strengthen farmers’ resilience to climate change. The objective of this report is to improve the knowledge base that informs investment decisions in land management technologies that purposefully sequester soil carbon. both in the role their biomass plays in sequestering carbon and in providing habitat for biodiversity. where the challenge is most acute. Higher income urban populations have more diverse diets that feature a variety of high-value food sources. Projected increases in demand for food and bioenergy by 2050 have profound implications for the pressure that agriculture wields on forests and other natural ecosystems in the tropics. It is a major determinant of the soil’s ability to hold and release water and other nutrients that are essential for plants and their root systems to grow. which is the sector of the global economy that is most vulnerable to the effects of global warming. The second exercise was to apply an ecosystem simulation modeling technique to predict future carbon storage in global cropland soils. The onus of this challenge falls on agriculture. Soil carbon also plays an important role in maintaining the biotic habitats that make land management systems sustainable. These ecosystems are vital. The findings reported are based on three exercises. Asia. accounting for one-third of global greenhouse gas (GHG) emissions. such as more variable rainfall and more extreme weather-generated events. Because soil is the basic resource in agricultural and forest land use. Climate-smart agriculture (CSA) seeks to increase productivity in an environmentally and socially sustainable way. and reduce the impact of climate change on agricultural ecosystems. they become a massive source of GHG emissions. are one of the principal contributors to climate change. When they are lost. such as livestock that are more resource intensive to produce and process. involving the implementation of land-use systems and management practices that enable humans to maximize the economic and social benefits from land while maintaining or enhancing the ecosystem services that land resources provide. The third consisted of a series of estimations of marginal abatement costs and trade-offs to assess the cost-effectiveness of deploying the land management technologies for climate-smart agriculture. Based on these developments. This adds to the challenge of maintaining and preserving the resilience of both natural and agricultural ecosystems. At the same time. A key element of CSA is sustainable land management (SLM). The current human population of 7 billion will increase to more than 9 billion by 2050. resilient. Soil carbon has a direct correlation with soil quality. and able to resist degradation. it is the central element of most SLM technologies.

relief. and $131 billion in Asia. climate. poor agricultural land management will intensify land degradation. and other biophysical features. These conventional agricultural practices include deforestation. barriers to adoption. The amount of support that governments will need to provide by the year 2030 to enable farmers to implement SLM practices are projected at US$20 billion in Africa. Certain techniques associated with sustainable land management can be incompatible with traditional practices. and often limited capacity to implement the techniques. At least four key messages emerge over the course of this report. increase farmers’ vulnerability to the effects of climate change.XV I EX EC UTIV E S UM M A RY reported in this document complement a number of related publications. and $1. including those emissions that result from land-use change in which carbon stocks become carbon sources as agricultural production expands into natural ecosystems. These include the need for significant up-front expenditures on the part of poorer farmers. and reductions in GHG emissions. $274 billion for Latin America. time. Conserving this terrestrial carbon represents a “least-cost opportunity” in terms of climate change adaptation and mitigation and is essential to increasing the resilience of agricultural ecosystems.4 trillion for Asia. the nonavailability of some inputs in the local markets. Maximizing Benefits and Managing Trade-Offs Soil carbon sequestration can be maximized by managing trade-offs across space. and judicious application of fertilizers can reduce these emissions directly and increase rates of soil carbon sequestration. Working at the landscape level is useful for addressing food security and rural livelihood issues and in responding to the impacts of climate change and contributing to its mitigation. and sectors. (Globally. grasslands. The third benefit delivered by SLM is to reduce the emissions of GHGs that emanate from agricultural production. but also nitrous oxide and methane—GHGs with extremely high impacts on global warming. SLM practices are alternatives to conventional agriculture in all three of these paths—conservation. The Dynamics of Soil Organic Carbon Different ecosystems store different amounts of carbon depending on their species compositions. and lead to the emission of additional GHGs into the atmosphere. and wetlands remain stored as carbon stocks. sustainable land management technologies can be beneficial to farmers because they can increase yields and reduce production costs. managing trade-offs. uncontrolled grazing. sequestration. including empirical lessons from recent project examples and policy briefs that were used as inputs at the Durban Climate Change Conference in November 2011. Investment in soil quality improvement practices such as erosion control. draining of wetlands. The first is carbon conservation. its reversal of agriculture’s negative impacts also presents profound contrast with conventional practices. and the need for targeted public support. and plowing and other forms of soil disturbance that release not only carbon dioxide into the atmosphere. which is equal to CARBON SEQUESTRATION IN AGRICULTURAL SOILS . The Need for Targeted Public Support Without public support for farmers. the burning of biomass. volumes of carbon are generally measured in gigatonnes [Gt]. The second benefit is carbon sequestration. Profitability In addition to storing soil carbon. In some instances. $41 billion in Latin America. lack of information about the potential of improved techniques. in which the growth of agricultural and natural biomass actively removes carbon from the atmosphere and stores it in soil and biomass. in which the large volumes of carbon stored in natural forests. and these relate to profitability. While it capitalizes more purposefully on the positive impacts of conservation and sequestration. soil types. the diffusion of new technologies relies on a level of social capital and experience with collective action that farmers simply do not yet have. water management. Barriers to Adoption and Up-Front Costs The adoption of sustainable land management practices can face a variety of socioeconomic and institutional barriers. Total private profits by the year 2030 are estimated at US$105 billion for Africa. Mechanisms for Carbon Enhancement in Agro-Ecosystems Sustainable land management delivers carbon benefits in three important ways.

9 159 Boreal forests 13.0 191 96.6 VEGETATION PROPORTION (%) SOILS PROPORTION (%) TOTAL 212 49.7 471 84.5 9 3.7 121 95.2 466 2. Soil carbon stocks also vary by ecosystem.1 100 62.5 428 Temperate forests 10. Boreal ecosystems are a particular concern. 1 billion tons.3 559 Tropical savannas 22.EX E C U T I V E S U MMARY X V II PHOTO E.5 8 4.4 59 37.3 127 Wetlands 3.477 19 81 100 . or metric tons in the United States. Conservation and protection are therefore widely recognized as major priorities.7 88 15.3 225 93.1: Terracing and Landscape Management in Bhutan Source: Curt Carnemark/World Bank.011 2.5 216 50. Soils hold more carbon than plant biomass (or vegetation) and account for 81 percent of the world’s terrestrial carbon stock.5 6 4. EC O N O M I C A N D S E CT OR WORK 16 151.) The amount of carbon stored in plant biomass ranges from 3 Gt in croplands to 212 Gt in tropical forests (table E1). et al.0 199 Tundra 9.7 131 Croplands Total Proportion (%) Source: Watson.0 304 Deserts 45.0 330 Temperate grasslands 12. from 100 Gt in temperate forests to 471 Gt in boreal forests. Robert.0 264 80. TABLE E1: Carbon Stocks in Vegetation and Top 1 Meter of Soils of World Biomes CARBON STOCKS (Gt C) AND PROPORTION IN THE ECOSYSTEM (%) BIOMES AREA (MILLION km2) Tropical forests 17.3 128 97. Because much of the soil organic carbon stored there is permafrost and wetlands.5 66 20. any large-scale melting caused by global warming will release massive volumes of carbon into the atmosphere. with the exception of limited areas selected for forest management. (2000).8 240 3 2. for instance.5 15 6. ranging.0 295 97.

Africa.500 Gt up to a 2-m depth.8–1.XV I I I EX EC UTIV E S UM M A RY TABLE E2: Estimates of Erosion-Induced Carbon Emission Across World Regions GROSS EROSION (Gt/YEAR) SOIL CARBON DISPLACED BY EROSION (2 TO 3 PERCENT OF SEDIMENT.0–6.30–0. Globally. Rapidly growing emissions are outpacing the growth in natural sinks (lands and oceans).92 Gt of carbon per year through soil erosion. depth.1–0.5 times the size of the biotic pool (560 Gt).2 0.0 Gt for Asia (table E2).0 0. and oceans. oil. residue removal.4 0.02–0. Theoretically. excessive fertilizers. Asia.16–0.1 0. the soil organic carbon pool comprises 1.44 Gt per year for Asia.16–0. tillage operations. bulk density.16 Europe 13. Agricultural soils must be prevented from being washed into streams and rivers where the relatively stable soil carbon pools are rapidly oxidized to carbon dioxide.2 0. The potential carbon sequestration is controlled primarily by pedological factors that set the physico-chemical maximum limit to storage of carbon in the soil. Globally.5–2.0 1.2–0. The amount changes over time depending on photosynthetic C added and the rate of its decay. However.1 4.2 0. vegetation. Such factors include soil texture and clay mineralogy. soils.30 to 0. This corresponds to carbon emissions ranging from 0. The soil organic carbon pool represents a dynamic balance between gains and losses.2 0. and leaching. Net primary productivity (NPP)—the rate of photosynthesis minus autotrophic respiration—is the major factor influencing attainable sequestration and is modified by above-ground versus below-ground allocation.04–0. and South America emit between 0. residue removal. aeration.8–1. the soil carbon pool (also referred to as the pedologic pool) is estimated at 2.8 to 1. These sinks currently remove an average of 55 percent of all anthropogenic carbon dioxide emissions.6–0.6 Gt for Oceania to 74. Under undisturbed natural conditions. biomass burning.1 0.04 201.2 REGION Oceania Total Source: Lal. The two most important anthropogenic processes responsible for the release of carbon dioxide into the atmosphere are the burning of fossil fuels (coal. only 50 to 66 percent of this capacity is attainable through the adoption of sustainable land management practices. Because soil organic matter is concentrated on the soil surface. CARBON SEQUESTRATION IN AGRICULTURAL SOILS .44 South America 39. and proportion of coarse fragments.9 0. while the soil inorganic carbon and elemental pools make up the remaining 950 Gt (Batjes 1996).4 0. and natural gas) and land use.8–1. Climate has both direct and indirect effects on attainable sequestration.02 to 0. Gt C/YEAR) EMISSION (20 PERCENT OF DISPLACED SOIL CARBON. organic matter decomposition. The global carbon cycle describes the transfer of carbon in the earth’s atmosphere.8 0. the potential soil carbon sequestration capacity is equivalent to the cumulative historical carbon loss. Out of this. and drainage of peat lands) is between 0. Attainable carbon sequestration is determined by factors that limit the input of carbon to the soil system. Soils are critically important in determining global carbon cycle dynamics because they serve as the link between the atmosphere. and drainage.1 Gt carbon per year.60 and 0. vegetation.12–0. Land management practices that increase carbon input through increasing NPP tend to increase the attainable carbon sequestration to nearer to the potential level. The soil carbon pool is more than 3 times the size of the atmospheric pool (760 Gt) and about 4.6 0. 201 Gt of soil is lost to erosion. inputs of carbon from litter fall and root biomass are cycled by output through erosion.04 Gt per year for Oceania to 0. tillage.08 7. corresponding to 0. R. Gt C/YEAR) Africa 38.2 Gt of emitted carbon per year. and oceans. 50 years ago they removed 60 percent. (2003). Actual carbon sequestration is determined by land management factors that reduce carbon storage such as erosion. accelerated soil erosion leads to progressive depletion of soil carbon. Decomposition rate increases with temperature but decreases with increasingly anaerobic conditions.24 Asia 74. The annual rate of soil loss ranges from 7. Soil erosion is the major land degradation process that emits soil carbon.7 and 2. The efficiency of oceans and lands as carbon dioxide sinks has declined over time.550 Gt.24 North America 28. The current rate of carbon loss due to land-use change (deforestation) and related land-change processes (erosion.

the assessment is used for national or regional accounting or for a carbon offset project. whether. Although simulation models can have limited accuracy. and inelastic neutron scattering (INS). they are a cost-effective means of estimating GHG emissions in space and time under a wide range of biophysical and agricultural management conditions. for instance. but most of its challenges can be addressed through an appropriate design that accounts for soil spatial variation. and water management can optimize soil respiration in addition to improving soil carbon leading to the triple win of enhanced agricultural productivity. spatially explicit biogeochemical modeling. Direct methods are more precise and accurate but also more time and labor intensive as well as very expensive. the cellulose absorption index. and remote sensing. and amounts of crop residues. leaf area index. A small change in soil respiration can significantly alter the balance of atmospheric carbon dioxide concentration compared to soil carbon stores. The degree and nature of sampling depend on the objectives of the carbon assessment objective. estimated at 75 to 100 Gt carbon per year. IR spectroscopy has proven valuable in developing soil spectral libraries and for rapid characterization of soil properties for soil quality monitoring and other agricultural applications in developed and developing countries. One of the more important indirect methods involves the use of simulation models that project changes in soil organic carbon under varying climate. derived from remote imaging spectroscopy. existing databases. Some in situ soil carbon analytical methods are being developed with the objective of offering increased accuracy. The data can be particularly useful in scaling-up site-specific information to larger scales of magnitude. the flux of microbially and plant-respired carbon dioxide. The most established type of direct soil carbon assessment entails collecting soil samples in the field and analyzing them in the laboratory using combustion techniques. sampling depth and volume. These parameters are fed into biogeochemical models to predict soil carbon sequestration. While LIBS and INS technologies are still in their infancy. soil properties. crop rotations. and soil organic matter decomposition. Approaches to Soil Carbon Assessment Soil carbon assessment in different parts of the world requires methods that are appropriate to the circumstances. and estimation of the marginal cost of carbon sequestration. When other factors are at optimum. Indirect estimation of soil organic carbon changes over large areas using simulation models has become increasingly important.EX E C U T I V E S U MMARY Soil respiration. particularly in the context of developing countries in which land resources data are scarce. has been used to infer tillage intensity and residue quantity. All of this is critical information used for input into models. precision. adaptation. crop yields and location. Ensuring this comparability warrants serious international priority. development of measurement protocols. laboratory analyses. leading to reduced crop production and decreased resilience of the soil ecosystem. In the case of carbon projects. use of cover crops (green manure). is the next largest terrestrial carbon flux following photosynthesis. management history. tillage practices. application of manure. Conventional tillage leads to the destruction of soil aggregates. Multitemporal moderate resolution remote sensing such as the Landsat Thematic Mapper and Moderate EC O N O M I C A N D S E CT OR WORK X IX . and scaling-up the results to the entire project area. geographical information systems. Field sampling is technically challenging. and cost-effectiveness over conventional ex situ methods. The selection of landscape monitoring units is based on the responsiveness of the area to land management practices as determined by climate. These include selection of landscape units suitable for monitoring soil carbon changes. Soil respiration is a potentially important mechanism of positive feedback to climate change. credible and cost-effective techniques of monitoring changes in soil carbon still need to be developed. and mitigation. Indirect methods are needed to fill knowledge gaps about the biogeochemical processes involved in soil carbon sequestration. and management conditions. soil. conservation tillage. use of deep-rooted crops. laser-induced breakdown spectroscopy (LIBS). The variety of methods that have been developed and tested for use in different countries raises concerns about their comparability. measurement of bulk density. Each context will require a differing degree of granularity and measurement set to assess uncertainty in the estimates. excessive respiration. near-IR spectroscopy. Monitoring and verifying soil carbon sequestration at the project or regional scale require five activities. Scaling-up to larger areas requires integration from a variety of sources including field measurements. Soil carbon assessment methods can be broadly classified into direct and indirect methods. models. use of remote sensing to estimate soil organic carbon controlling parameters. and availability of historical data. Remote sensing can provide information on net primary productivity. other ancillary field measurements. The in situ soil carbon analytical methods include mid-infrared (IR) spectroscopy. Protocols for temporally repeated measurements at fixed locations will generally include stratification and selection of sampling sites. depending on whether carbon content in soil samples is directly measured or inferred through a proxy variable. Recently.

irrespective of land management practices. Canada’s National Forest Carbon Monitoring. thereby indicating the overall effects on the carbon balance. enteric methane emissions.500 mm. rice methane emissions. A detailed analysis of lessons learned in testing EX-ACT in World Bank agriculture projects can be found in a separate report. referred to as Sustainable Agricultural Land Management (SALM).2: Crop Residue Management in Irrigated Fields in Indonesia Source: Curt Carnemark/World Bank.XX EX EC UTIV E S UM M A RY Resolution Imaging Spectroradiometer can provide information such as land-use and land-cover change. and manure methane and nitrous oxide emissions. higher sequestration rates were observed in the wettest locations with annual precipitation above 1. The Agriculture and Land Use National Greenhouse Gas Inventory Software tool was recently developed by Colorado State University to support countries’ efforts to understand current emission trends and the influence of land-use and management alternatives on future emissions. crop rotations. livestock. In this study. as well as non-CO2 GHG emissions from biomass burning. Indonesia’s National Carbon Accounting System. Accounting. soil C stocks. The tool can be used to estimate emissions and removals associated with biomass C stocks. fisheries. CARBON SEQUESTRATION IN AGRICULTURAL SOILS . soil nitrous oxide emissions. restricted to industrialized countries and a handful of developing countries. The Food and Agriculture Organization of the United Nations has developed the Ex Ante Appraisal Carbon-Balance Tool (EX-ACT) to assess GHGs in the agricultural sector. The BioCarbon Fund of the World Bank has also developed a methodology to encourage adoption of sustainable land management practices by small-scale farmers in developing countries. provides a protocol for quantifying carbon emissions and removals and includes guidelines for identifying baseline scenario and assessing additionality in all carbon pools relevant to sustainable land management projects. Monitoring trends in soil carbon over a large geographical area through repeated sampling is. EX-ACT can provide ex ante assessments of the impact of agriculture and related forestry. and water development projects on GHG emissions and carbon sequestration. The methodology. PHOTO E. and Reporting System. for the most part. which can markedly improve our ability to scale-up soil carbon assessments. Factors Affecting Soil Carbon Sequestration Climate significantly influences large-scale patterns of soil carbon sequestration. and New Zealand’s Carbon Accounting System. Examples of national carbon accounting system and tools include Australia’s National Carbon Accounting System. and soil moisture.

5 t CO2e per ha per year across the three regions. formed principally in humid tropical zones under rain forest. the highest sequestration rates and variability are observed in oxisols. with lower or even negative rates in the short term. while those of crop rotation were 0. Process emissions are those arising from fuel and energy use. GHG abatements of cover crops were 1. carbon sequestration rates and variability are highest on inceptisols—relatively young soils that constitute about 9 percent of soils in the tropics. The tool comprises several land management scenarios reflecting situations typically encountered in agricultural projects. With most practices.1 Greenhouse Gas Mitigation by Sustainable Land Management Technologies The climate benefits of sustainable land management technologies are measured by the net rate of carbon sequestration adjusted for emissions associated with the technologies—a measurement referred to as the abatement rate.7 t CO2e per ha per year across the regions. scrub. Land emissions are the differences between emissions of nitrous oxides and methane by conventional and improved practices. and cropping systems also affect carbon sequestration under crop rotation. Differences in soils. Oxisols comprise about 24 percent of tropical land mass and are typically found on old landscapes that have been subject to shifting cultivation for some time. In Latin America. and removal of the residues for other uses. The emissions associated with the technologies are classified as land emissions and process emissions. Soil type is significant to soil carbon sequestration as well. Information on carbon sequestration potential of a location can be derived by point-and-click or by searching using place names. There is a tendency toward higher carbon sequestration rates in triple cropping systems. grazing.. Improved irrigation generated low to moderately high abatement rates (0.worldbank.23 t CO2e per ha per year compared to 0.org/SoilCarbonSequestration/). sugarcane. and other grain crops.2 to 2. The Internet GIS database provides per-hectare estimates of soil carbon sequestration under different land management practices for a period of 20 to 25 years. Most of the potential soil carbon sequestration takes place within the first 20 to 30 years of adopting improved land management practices. while semi-humid areas have higher sequestration rates than their semi-arid counterparts. the abatement rate of inorganic fertilizer is −0. rice. In Africa and Latin America. maize or sorghum followed by legumes) or a variety from the previous crop.g. Soils with higher clay content sequester carbon at higher rates. No-tillage and residue management generated abatement rates ranging from 0. Supplemental irrigation and water harvesting are needed to minimize production risks in dry land agriculture. the highest rates of sequestration are achieved in the intermediate term. Users can download data from the database and integrate them with other GIS information to estimate soil carbon stock changes for different agricultural projects.7 to 2. EC O N O M I C A N D S E CT OR WORK XXI . climate. The succeeding crop may be of a different species (e.29 t CO2e per ha per year for Africa. In Asia.4 t CO2e per ha per year. Increases in productivity from nitrogen fertilizers need to be considered against the increased emission of GHGs from soils as well as the energy-related emissions associated with the fertilizer’s production and transport. or savanna vegetation. Cover crops improve soil quality by increasing soil organic carbon through their biomass. and the planned rotation may be for 2 or more years. Crop rotation is the deliberate order of specific crops sown on the same field. These rates represent the marginal carbon benefit of mulching or incorporating residues relative to burning.7 to 1. Sites in warmer and middle temperature regions tend to accumulate soil carbon more rapidly than those in colder regions. The abatement rate is expressed in tons of carbon dioxide equivalent (t CO2e) per hectare (ha) per year.4 t CO2e per ha 1 The World Bank has posted a useful geographical information system tool on the Internet that summarizes the results of a series of ecosystem modeling exercises (see http://www-esd. Cover crops and crop rotation are key complementary practices for successful implementation of no-tillage.13 t CO2e per ha per year for Asia and 0. The greenhouse mitigation of manure is much higher at about 2.9 to 3.EX E C U T I V E S U MMARY There was also a trend to lower sequestration rates in the coolest (mean annual temperature less than 20°C) and warmest (mean annual temperature greater than 30°C) conditions. Commonly applied residues on croplands include biomass from trees. although variation is high. The patterns of change in sequestration rates are nonlinear and differ between major types of practices. Timing is another factor that warrants careful consideration when introducing improved land management practices that increase carbon sequestration. and they also help in improving soil aggregate stability and protecting the soil from surface runoff. They also sequester carbon in the soil.2 to 3.5 t CO2e per ha per year.

er till to cro -p re er ps sid en ue n m m ial an a n pa u st age re ur m een in to-f t clu or e in de t st te r e r pa c cr es st rop opp ur e.es rie cr i rs op n f af far ield fo m r a es in im lley tat g pr fa ion ov rm ed in fa g ll bi ow oc ha r XXI I EX EC UTIV E S UM M A RY FIGURE E1: Abatement Rates of the Land Management Practices (t CO2e Per Hectare Per Year) 12 10 Africa 8 6 4 2 0 18 16 14 Asia 14 12 10 8 6 4 2 0 16 Latin America 12 10 8 6 4 2 0 -2 Source: This study.tio -t gr n no o-p azin or lant g re ati du on c an c nu ov ed al.ing to fo r -p lan est ta ti bi on oc ha r no ica o l fe re int r re rtil s e d iz ap idue nsi uce er f pl ica ma y ro d ti tio na tat ll n g io re of em n du m en ce ulc t d.ch e im mic pr al ov fe di ed rtili ve irr ze ig r r in sify ati te o r ns ot n gr re ify atio as du ro n sla ce ta nd d.he gr s c cr op ove azin -to r c g -g ro ra ps im ss pr ov m lan ed a d n an in irri ure g c n l in ua ud at i te lns to e t on ive -pe ree w at ve ren s er ge ni ha ta al b in rve les te rs rc tin r cr op bi opp g -to ofe ing -p r cr lan tiliz op ta er -to tio -fo n r bi est oc ha r m ch e ro ch ta em tio i n ca in l f te er ns til ifi ize ro ca r ta tio r e tio s id n n di m ue ve u s rs lch ifi e c s no atio co til n ve lag ot rc e he ro rs ps m o pa il a t an st m er ure ur en ra e d cin w imp em g at ro en er v ts h e cr in arv me os t e nt e in s s rcr stin clu lo op g de pe pi tre tre /bar ng e. CARBON SEQUESTRATION IN AGRICULTURAL SOILS .-to.

3 to 6. Conversion of cropland to forest or pasture to plantation resulted in an abatement of 6. land-use changes away from cropland to agroforestry or plantations provide more convincing examples where it is useful to think of both aboveand below-ground sequestration rates at the same time and possible trade-offs or interactions between them.5 t CO2e per ha per year. Abatement rates of agroforestry systems. 8. but its impact on crop productivity and soil resilience is still uncertain. In general. 7. Application of biochar. on average. Process and land emissions under irrigation can significantly offset gains from carbon sequestration. averaged 3. Apart from energy-related emissions. PHOTO E.3 for intercropping (the growing of crops near existing trees).9 to 4. However.EX E C U T I V E S U MMARY per year). and 4. By definition.7 t CO2e per ha per year.7 t CO2e per ha per year). Terracing and construction of slope barriers on sloping lands for soil and water conservation produced abatements of 2. the process of concentrating runoff from a larger area for use in a smaller target area. they should be based on whole farm systems analysis that comprehensively assesses the productivity. 4. resulted in the highest overall GHG abatement rate (10.5 for tree-crop farming.3 t CO2e per ha per year. The average abatement rates in t CO2e per ha per year are 7. Mid-season drainage is a viable practice to reduce such emissions.21 t CO2e per ha per year.7 to 7. The GHG abatement of water harvesting.3 to 15. whereas conversion of cropland to grassland produced GHG mitigation of 2. a critical issue for soil carbon sequestration activities in irrigated areas is reduced emissions of methane from rice fields. while conversion of cropland to plantation generated an abatement of 5. most of the potential impact of changes in agricultural practices on carbon stocks is below ground. Decisions to adopt any of the land management practices should not be based solely on their respective climate mitigation benefits.3: Water Management in a Field in India Source: Ray Witlin/World Bank.7 for improved fallow (involving the use of fast-growing trees to accelerate soil rehabilitation).6 for alley farming (the growing of crops simultaneously in alleys of perennial. integrated land-use systems combining trees and shrubs with crops and livestock. biochar production should not deplete the soil of the crop residues needed to protect against erosion and increase soil resilience. Pasture improvement generated an abatement of 3.7 for croplands where trees are introduced.4 to 5. Rather. are fairly high.6 t CO2e per ha per year. preferably leguminous trees or shrubs).6 to 6. The impacts of land-use changes on tree-based systems are also relatively large. This is due to the relatively large time-averaged biomass of trees compared to crops.8 t CO2e per ha per year. EC O N O M I C A N D S E CT OR WORK X X III .

Capitalizing on Synergies and Managing Trade-Offs in Soil Carbon Sequestration Synergies occur when there is a positive correlation between carbon sequestration and profitability (where profitability refers to the net present value of implementing the land management practices). and increases crop yields. sorghum. and groundnut in agroforestry systems. The profitability of no-tillage systems results mainly from the reduced labor requirement for seedbed preparation and other tillage operations compared to conventional tillage systems. The pattern of increase in yield. Excessive fertilizer use is less environmentally friendly. Increasing food security under a changing climate requires the analysis and identification of the land management technologies that maximize synergies and minimize trade-offs. however.4: Maize Growing under Faidherbia Albida Trees in Tanzania Source: World Agroforestry Centre. and establishing barriers across sloping areas tend to take land out of production for a significant period of time. Afforestation. improved fallow (including trees in croplands). Judicious fertilizer application counters soil nutrient depletion. will most likely generate optimum social benefits. and environmental load of the system. reduces deforestation and expansion of cultivation to marginal areas. due to nitrous oxide emissions associated with high application rates of nitrogen fertilizers and fossil fuel–based emissions associated with fertilizer production and transportation. The time-averaged. Profitability of Soil Carbon Sequestration In addition to storing soil carbon. Increases in crop yields derive from the ability of the land management technologies to maintain soil organic matter and biological activity at levels suitable for soil fertility. A plot of profit versus carbon sequestration reveals synergies in two agroforestry systems—intercropping and alley farming (top right quadrant of figure E2). land management technologies in the lower right quadrant have high mitigation potentials but are modestly profitable. however. millet. yields have doubled for maize and increased by 60 percent for cotton compared to the conventional tillage system. They reduce the amount of land available for cultivation in the short run but can lead to overall increases in productivity and improved resilience in the long run.XXI V EX EC UTIV E S UM M A RY PHOTO E. In Zambia. Inorganic fertilizers also show relatively high profits because they provide nutrients that can be readily absorbed by plants. but relatively high labor inputs are required to reduce competition effects of trees from negatively impacting crop growth. above-ground CARBON SEQUESTRATION IN AGRICULTURAL SOILS . on-farm resource use. Farmers also frequently reported significant crop yield increases for maize. In figure E2. Farm-scale management decisions. cotton. particularly the influence of public policy and markets. sustainable land management technologies can be beneficial to farmers by increasing yields and reducing production costs. varies from crop to crop. taken within a wider socioeconomic context. Trade-offs occur when attempts to increase carbon storage reduce profits.

Also. EC O N O M I C A N D S E CT OR WORK .000 No-tillage Inorganic fertilizer Intercropping 100 Alley farming Manure Cover crops Soil amendments Crop residues Include trees Terracing 10 Rotation intensification Rotation diversification Afforestation Tree crop farming Rainwater harvesting Improved fallow Cross slope barriers 1 0 2 4 6 8 10 carbon dioxide sequestered (ton per hectare per year) Source: This study.5: Crop Harvesting in Mali. The relatively high profitability of no-tillage derives primarily from the decrease in production costs after the establishment of the system.EX E C U T I V E S U MMARY XXV PHOTO E. Yields also increase with manure application and accumulation of soil carbon. Manure is less profitable than inorganic fertilizer because of the labor costs associated with collecting and processing manure (top left quadrant of figure E2). The Biomass Is Smaller Compared to that of Agroforestry Systems Source: Curt Carnemark/World Bank. Judicious fertilizer application increases crop yields and profitability. biomass of crop residues and other technologies in the lower left quadrant of figure E2 is relatively small compared to that of agroforestry systems. FIGURE E2: Trade-Offs Between Profitability and Carbon Sequestration of Sustainable Land Management Technologies profit per tone of carbon dioxide sequestered (US $) 1. but with patterns that depend on crop type. the biomass of crop residues does not accumulate easily. resulting in lower mitigation benefits.

Thus. figure E3) reflects the use of subsidies in spurring farmers’ access to the technology. and the support helps improve targeting through market-smart subsidies while providing impetus for private sector input development. and mitigation benefits in agriculture. vouchers. FIGURE E3: Relationship Between Private Benefits and Public Costs private benefit (per tonne of carbon dioxide sequestered) 1000 No-tillage Inorganic fertilizer Intercropping 100 Alley farming Manure Cover crops Terracing Include trees Crop residues Crop rotation 10 Afforestation Tree crop farming Improved fallow Rainwater harvesting Cross slope barriers 1 0 3 5 8 10 13 public cost ($ per tonne of carbon dioxide sequestered) Source: This study. respectively). They include investments in seeds and seedlings. investments in improved land management. and pollination. The landscape approach entails the integrated planning of land. watershed. Public Costs of Soil Carbon Sequestration Public cost refers to government support toward the implementation of land management practices. cover crops. time. Working at the landscape level within an ecosystems approach is useful for addressing food security and rural livelihood issues and in responding to the impacts of climate change and contributing to its mitigation. and rainwater harvesting with lower profits and also manure and no tillage that generate relatively higher profits require minimal government support (lower left and upper left quadrants of figure E3. and water at local. extension services. matching grants. freshwater cycling. difficult targeting. The low profits suggest that farmers may be reluctant to privately invest in these technologies. the subsidies help achieve social rather than economic objectives. Crop residues. and crowding out of commercial sales. and land tenure rather than on input support is generally more effective. Examples of market-smart subsidies include demonstration packs. The relatively high public cost of inorganic fertilizer (top right quadrant. and is more sustainable in the long run. agriculture. biodiversity protection. Public support that focuses on research. Technologies that involve significant change in land use (such as afforestation and improved fallows) and landscape alteration (such as terracing and cross-slope barriers) incur high public costs but generate low private benefits (lower right quadrant of figure E3). adaptation. and loan guarantees. Sustainable land management interventions should be planned and implemented in a coordinated manner across space. carbon storage. Strong public involvement in these technologies is required given their relatively high mitigation potentials. benefits more farmers. and regional scales to ensure that synergies are properly captured. The pattern of public support is as crucial as the amount of support for full realization of productivity. The landscape approach provides a framework for the better management of ecosystem services. Fertilizer subsidies are associated with high fiscal costs. fisheries. and other administrative costs. fertilizer subsidies are appropriate in situations when the economic benefits clearly exceed costs. forests. These technologies generally have low mitigation potentials. input subsidies.XXV I EX EC UTIV E S UM M A RY The trade-offs exhibited by the land management technologies have important implications for land-use decision making. crop rotation. such as agricultural productivity. and sectors. CARBON SEQUESTRATION IN AGRICULTURAL SOILS .

Factors affecting adoption tend to be more specific to the land management technologies.368.4 trillion in Asia.097 319.259.505 108.224.8 150.926 120.1 159. and impact of such land management technologies. B2 = a world more divided but more ecologically friendly.EX E C U T I V E S U MMARY X X V II The overall biophysical mitigation.3 A1b 6. lack of information on the potentials of alternative techniques of farming and limited capacity is a major constraint in many developing countries. and Public Costs of the Land Management Technologies by 2030 SCENARIO TECHNICAL POTENTIAL (MILLION TONS CO2-eq) PRIVATE BENEFITS (US$.3 A2 3.4 42.0 Gt CO2-eq for Asia (table E3).4 19.4 55. and the costs of soil carbon sequestration by 2030 depend on the emission scenarios influenced by a wide range of driving forces from demographic to social and economic developments. Secure land rights is a precondition for climate-smart agriculture as it provides incentive for local communities to manage land more sustainably.8 A2 3. potential savings.5 131. Better market prices for crops and other agricultural produce are crucial.425 279.7 B2 3.6 A1b 3.3 143.3 Gt CO2-eq for Latin America to 7.6 19.9 B2 2. their adoption faces many socioeconomic and institutional barriers: Most of the land management technologies require significant up-front expenditure that poor farmers cannot afford. Ill-defined land ownership may inhibit sustainable land management changes.678 1.4 B1 2.8 40. when technologies are inconsistent with community rules and traditional practices. EC O N O M I C A N D S E CT OR WORK .310.388 1. A2 = a world more divided and independently operating self-reliant nations. The total mitigation potential varies from 2. A1b = a world more integrated with a balanced emphasis on all energy sources.7 A2 6.9 22. TABLE E3: Technical Mitigation Potential. BILLION ) Africa B1 3.538 288. Table E4 suggests that lack of credit and inputs and land tenure problems are by far the most important factors for adoption across the range of technologies. while total public costs range from US$20 billion in Africa to $160 billion in Asia. Barriers to the Adoption of Sustainable Land Management Practices Despite the fact that improved land management technologies generate private and public benefits.6 B2 7.321 273. and willingness and ability to work together is crucial for many technologies such as improved irrigation and communal pastures. their adoption is often resisted.977 1. BILLION ) PUBLIC COSTS (US$. diffusion. However. The absence of collective action will hinder successful uptake.1 Asia Latin America Source: This study.678 111.8 A1b 2. Total private profits range from US$105 billion in Africa to $1.3 B1 5.007 1.8 44. improved availability of inputs is a necessary but insufficient condition for adoption of land management practices.448 105. Notes: B1 = a world more integrated and more ecologically friendly. the nonavailability of inputs in the local markets can be a significant obstacle. Private Benefits.4 20.

Liniger. Some public policies that can potentially incentivize carbon sequestration include the following options.. 2.. progress in incorporating it into the UN Framework Convention on Climate Change (UNFCCC) has been slower than many people hoped for. R. Given the tremendous significance that agriculture has for the global climate. residue management. H. and Gurtner. 2011. 1. Readiness for carbon sequestration and climate-smart agriculture can be achieved through improved extension services and training in relevant land management technologies for different locales. World Overview of Conservation Approaches and Technologies and Food and Agriculture Organization of the United Nations. *** = High importance. conservation agriculture. south-south knowledge exchange. the real and potential contributions the sector can and does make in terms of sequestering carbon in agricultural biomass and soils were for the most part omitted.. regional platforms. This is vitally important because agriculture needs to be fully incorporated into adaptation and mitigation strategies. requiring training and practical experience of those promoting its adoption. 2011. While the negative impacts of agricultural production in terms of land-use change and GHG emissions were reasonably well covered by the convention. Hauert. Learning hubs. Policy Implications Private benefits that drive land-use decisions often fall short of social costs. thus. carbon sequestration may not reach the optimal level from a social point of view unless some mechanisms exist to encourage farmers. At the 17th Conference of Parties to the UNFCCC in Durban.XXV I I I EX EC UTIV E S UM M A RY TABLE E4: Relative Importance of Different Factors for Adopting Improved Land Management Practices LAND MANAGEMENT TECHNOLOGY INPUTS/ CREDITS MARKET ACCESS TRAINING/ EDUCATION LAND TENURE RESEARCH INFRASTRUCTURE Inorganic fertilizer *** ** ** ** * ** Manure ** ** * ** * ** Conservation agriculture ** ** *** ** ** * Rainwater harvesting ** ** ** *** ** ** Cross-slope barriers ** * ** ** ** * Improved fallows ** * * *** ** * Grazing management *** *** ** *** ** * Source: Synthesized from Liniger et al. Existing national policies. strategies. CARBON SEQUESTRATION IN AGRICULTURAL SOILS . M. the parties asked the UNFCCC Subsidiary Body for Scientific and Technological Advice to explore the possibility of a formal work program on agriculture. the international community has recognized the importance of integrating agriculture into the ongoing negotiations on the international climate change regime. ** = Moderate importance. and investment plans should be strengthened to form the basis for scaling-up investments for climate-smart agriculture. There is a need to build the technical and institutional capacity of government ministries to implement climate-smart agriculture programs. A more practical and thorough picture makes it possible for agriculture to be rewarded for its positive environmental impacts and to be an integral part of the solution as well as part of the problem. Sustainable Land Management in Practice—Guidelines and Best Practices for SubSaharan Africa. the farming system involving no-tillage. For instance. and use of cover crops is highly knowledge intensive. Strengthen the capacity of governments to implement climate-smart agriculture. South Africa. Global cooperative agreement. As a result. P. scientific research. Key * = Low importance. Behavioral change through education and extension services is required to enable change-over to improved land management technologies. and technical support mechanisms may increase innovation and facilitate adoption of improved land management technologies. The knowledge base of land management practices at the local level can be also improved through careful targeting of capacity development programs. in November 2011. Countries must be prepared to access new and additional finance. C. Mekdaschi Studer. Redressing this omission promises to foster a more balanced perspective in which food security is not necessarily at odds with climate change adaptation and mitigation (an unworkable conflict in which longer term environmental concerns are virtually guaranteed to universally lose out politically to the more immediate concern of food supply).

private. While this may appear a tall order in countries with severe budget constraints. and development finance will be required to scale-up improved land management practices. grant funding or loans may be more suitable to overcoming adoption barriers. payment for an ecosystem services scheme could be used to support farmers and break the adoption barrier. Introducing policies and incentives that provide an enabling environment for private sector investment can increase overall investment. finite public resources can be more selectively targeted using the criteria given above—prioritizing technologies that generate no short-term returns and those that most effectively address the barriers that prevent prospective adopters from moving forward. Raise the level of national investment in agriculture. Bundling agricultural credit and insurance together and providing different forms of risk management such as index-based weather insurance or weather derivatives are areas of private investment that can be encouraged through public policy and public-private partnerships. Particular attention should go to encouraging private financial service providers to tailor instruments that enable farmers who adopt SLM practices to overcome the barriers described above. Boost financial support for early action. However. public investment is only one sphere. Nationally owned climate-smart agricultural policies and action frameworks will increase the adoption of sustainable land management practices. relatively affordable technologies that generate quick and demonstrable benefits may warrant priority and potentially establish some of the channels through which more sophisticated technologies are dispersed in the future. particularly when government priorities translate clearly into business opportunities and certain areas of investment are looked upon favorably by public officials and institutions. This private investment can be targeted to some degree as well. EC O N O M I C A N D S E CT OR WORK X X IX . 4. For technologies that generate significant private returns. In some cases. For technologies such as conservation agriculture that require specific machinery inputs and significant up-front costs. Integrating sources of climate finance with those that support food security may be one of the most promising ways to deliver to climate-smart agriculture the resources it requires. 5. A blend of public. and developing improved seeds and seedlings.EX E C U T I V E S U MMARY 3. There is also the potential for carbon finance to support farmers during the initial period before the trees in agroforestry systems generate an economic return. Public investment can also be used to leverage private investment in areas such as research and development. establishing tree plantations. and involving the private sector in climate-smart agriculture and sustainable land management is the other. Create enabling environments for private sector participation.

.

Agriculture is the primary driver of deforestation in many developing countries. EC O N O M I C A N D S E CT OR WORK Nitrous oxide from soils. enhancing the resilience of natural ecosystems.1). Under optimistic lower end projections of temperature rise. climate change may reduce crop yields by 10 to 20 percent (Jones and Thornton 2009). and energy will intensify in an attempt to meet the need for food. 12% Enteric fermentation.1 C H A P T E R 1 — I N T RODUCT ION Chapter 1: 1. while increased incidence of droughts and floods may lead to a sharp increase in prices of some of the main food crops by the 2050s. where possible.1: Contribution of Different Sectors to Greenhouse Gas Emissions Buildings 8% Manure mgt. 2010) The agriculture sector has a pivotal role to play in mitigating greenhouse gas (GHG) emissions. Over this period. Davis. About 55 percent of the new FIGURE 1. globalization may further expose the food system to the vagaries of economic and political forces. 11% Industry 19% Agriculture 14% Energy 26% Waste 3% Transport 13% Source: IPCC 2007. and the full implications in terms of productivity and food security are uncertain (Gornall et al. The net increase in agricultural land during the 1980s and 1990s was more than 100 million ha across the tropics. Agriculture is highly vulnerable to climate change and needs to adapt to changing climate conditions. 32% . Competition for land.1 INTRODUCTION FOOD SECURITY UNDER A CHANGING CLIMATE Ensuring food security under changing climate conditions is one of the major challenges of our era. Agriculture and land-use change currently account for about one-third of total emissions (figure 1. and fiber and will contribute to economic development and poverty reduction. fuel. and Lobell 2010). water. Various projections suggest that global food requirements must increase by 70 to 100 percent by 2050 (Burney. Smith et al. There are about 925 million food-insecure people in the world—about 16 percent of the population in developing countries. Climate change will also impact agriculture through effects on pests and disease. Global population will increase from 7 billion currently to over 9 billion people by 2050. 2008. 38% Biomass burning. in addition to maintaining and. 7% Forestry 17% Rice production. creating a demand for a more diverse diet that requires additional resources to produce. The interactions between ecosystems and climate change are complex.

agricultural land in the tropics came at the expense of intact forests. and reduce agriculture’s contribution to climate change by reducing GHG emissions and increasing soil carbon storage. the fundamental cause of declining crop productivity in developing countries. 2010. CARBON SEQUESTRATION IN AGRICULTURAL SOILS . and enhancing resilience to climate change call for alternative approaches to practicing agriculture. Asia. The overall increase in grain productivity in Africa. Soil carbon influences five major functions of the soil (Larson and Pierce 1991). defined as the ability of soils to function in natural and managed ecosystems. It also provides the biogeochemical linkage between other major carbon reservoirs. Soil is central to most SLM technologies because it is the basic resource for land use. 1980–2000 100% 90% 80% 70% Water 60% Plantations 50% Shrubs 40% Disturbed forests 30% Intact forests 20% 10% As ia ca h ut So tA W es Af st fri ric a ica h ut So Ea Am st Ea hut So er As ia ca fri lA ra nt Ce lA ra nt Ce Pa n -Tr m op er ics ica 0% Source: Redrawn from Gibbs et al. primarily in association with its organic constituent. and release water both for plants and for surface and groundwater recharge.CH A PTER 1 — INTR OD UC TION 2 FIGURE 1. reducing emissions. One of the key elements of CSA is sustainable land management (SLM) involving the implementation of land-use systems and management practices that enable humans to maximize the economic and social benefits from land while maintaining or enhancing the ecosystem services from land resources. Projected increases in demand for food and bioenergy by 2050 may further increase pressure on forests in the tropics with profound implications for an increase in GHG emissions.2). ƒ promote and sustain root growth. and hydrosphere. (2010). Even if emissions in all other sectors were eliminated by 2050. Soil carbon is held within the soil. ƒ maintain suitable biotic habitat. strengthen farmers’ resilience to climate change. Climatesmart agriculture (CSA) seeks to increase productivity in an environmentally and socially sustainable way. It supports all the terrestrial ecosystems that cycle much of the atmospheric and terrestrial carbon.2: Proportion of Agricultural Land Derived From Different Land Covers in the Tropics. namely the biosphere. namely the ability to ƒ accept.2). and Latin America due to such increase in soil organic carbon is estimated at 24 to 40 million tons per year (table 1. while another 28 percent came from the conversion of degraded forests (Gibbs et al. Increasing soil organic carbon can reverse soil fertility deterioration. and ƒ respond to management and resist degradation. growth in agricultural emissions under a business-as-usual world with a near doubling in food production would perpetuate climate change. ƒ accept. 1.1 indicates the potential increase in crop yields from increasing the soil organic carbon pool in the root zone by 1 ton C/ha/yr through SLM technologies. and release nutrients. hold. hold. atmosphere. Table 1. Soil carbon has a strong correlation with soil quality.2 CARBON BENEFITS THROUGH CLIMATE-SMART AGRICULTURE The triple imperatives of increasing productivity. figure 1.

7 13.5 0. TABLE 1.C H A P T E R 1 — I N T RODUCT ION 3 Furthermore.5–5. TABLE 1. and application of fertilizers and other amendments (World Bank 2010).1–6. Sustainable land management provides carbon benefits through three key processes. improving soil biodiversity. and wetlands have relatively high carbon stocks.02–0.4–0.2–0. Removal of the vegetation cover aggravates losses by soil erosion and increases the rate of decomposition due to changes in soil moisture and temperature regimes.6 1.7–1. limit GHG concentrations in the atmosphere. Sustainable land management practices are an alternative to several conventional agricultural practices that lead to emissions of GHG from the soil to the atmosphere. Zero tolerance for soil erosion is indispensable for soil carbon conservation. however. intercropping food crops with trees.0–1.2 1.0 Millet 0. Agricultural soils should be prevented from being washed to streams and rivers where the relatively stable soil C pools are rapidly oxidized to carbon dioxide (Lal 2003).5 0. plowing and soil disturbance (carbon dioxide). reducing the impacts of drought.3–0. reducing soil erosion. Source: Lal (2011). grasslands.5–6.1–0. namely carbon conservation.01–0.8 Beans 0.5–23. and reduce the impact of climate change on agricultural ecosystems.7 6.4 2. Some of this carbon.5–0.3 4.03 0. EC O N O M I C A N D S E CT OR WORK 0.9 0. and nitrous oxide).7 3. deforestation (carbon dioxide. accelerated soil erosion leads to progressive depletion of soil carbon. and integrated nutrient and water management also sequester carbon in the soil.2 4.1–8. water management.4–16. the removal of crop residues and cattle manure for fuel leads creates a negative carbon budget and must be prevented.9–4.7–7.0 0.2–0.4–0. new technologies such as deeper-rooted crops and pasture grasses can enhance original soil carbon up to a given equilibrium. Emission of these gases from agricultural ecosystems is increased through subsistence agricultural practices that do not invest in soil quality improvement practices such as erosion control.7–2. reduced emissions.6–1.6 3. Many natural land systems such as native forests. draining of wetlands (carbon dioxide and nitrous oxide). and nitrous oxide).2 4. as it offers the greatest least-cost opportunity for climate mitigation and ecosystem resilience.7 0.4–5.6–5. and uncontrolled grazing (carbon dioxide and nitrous oxide). Historically. can be recaptured through sustainable land management practices. methane.0–1. and increasing nutrient use efficiency.8–1.2 0.2: Estimated Increase in Grain Crop Production from Land Management Technologies That Sequester Soil Carbon (Million Tons/Year) CROP AFRICA ASIA LATIN AMERICA TOTAL Maize 0. Because soil organic matter is concentrated on the soil surface.1–0.8–1.4 Soybean Total Source: Lal (2003).6 3. and carbon sequestration. By adopting improved land management practices to increase soil carbon. methane.6–10.7 0. agricultural soils have lost more than 50 Gt (1 Gt = 1 billion tons) of carbon.8 0.9 0. reduce rural poverty. improving aeration and water-holding capacity.9 Rice 0.4 Sorghum 1.4–0. The use of crop residues as mulch.01 1. Soil carbon sequestration is the process by which atmospheric carbon dioxide is taken up by plants through photosynthesis and stored as carbon in biomass and soils.5 .9 9. farmers can increase crop yields. It entails replenishing lost carbon and adding new carbon (organic inputs) beyond original levels.1 23. Conserving this terrestrial carbon pool accumulated over millennia should be a major priority.1: Improvement in Crop Yields per Ton of Carbon in the Root Zone CROP POTENTIAL YIELD INCREASE (kg/ha) Maize 200–400 Wheat 20–70 Soybean 20–30 Cowpea 5–10 Rice 10–50 Millet 50–60 Soil carbon also enhances resilience to climate variability and change by improving soil structure and stability.3–1.4 Wheat 0.3 4.6–39.3–0. These conventional practices include biomass burning (that releases carbon dioxide. For instance.

Major exceptions are Guo and Gifford (2002) and Ogle et al. and Latin America. 2010. CARBON SEQUESTRATION IN AGRICULTURAL SOILS . IBSRAM Proceedings No. Guo. R. J.. W. E. The chapter concludes with brief information on carbon assessment in The World Bank’s sustainable land management projects portfolio. and Pasutian. Burke. “Implications of Climate Change for Agricultural Productivity in the Early Twenty-First Century. “Conservation and Enhancement of Soil Quality. S. F. R. “Sequestering Carbon in Soils of Agroecosystems. Latham.3 OBJECTIVES AND SCOPE OF THE REPORT The purpose of this report is to improve the knowledge base for facilitating investments in land management technologies that sequester soil organic carbon. Gornall. there is no single unifying volume that synthesizes knowledge on the impact of different land management practices on soil carbon sequestration rates across the world.” In Evaluation for Sustainable Land Management in the Developing World.. K. Climate Change 2007: Synthesis Report—Summary for Policymakers. J. This is one important element in decision-making for sustainable agricultural intensification.. M. P. ed..” Biogeochemistry 72: 87–121.. Camp. 12 (2): 175–203.. 2010.” Global Change Biology 8: 345–360.” Proceedings of the National Academy of Sciences 107 (26): 12052–12057.. but the sequestration rates in these papers are highly variable and not specific to local conditions. 2009. “Greenhouse Gas Mitigation by Agricultural Intensification. Environment Department.” Philosophical Transactions of the Royal Society B 363: 789–813. A. Bredit. Cambridge University Press. Ruesch. Ramankutty.2010. and Wiltshire. J. Betts. World Bank. The remainder of the report is organized as follows. et al.. J.. P. “Agricultural Management Impacts on Soil Organic Carbon Storage Under Moist and Dry Climatic Conditions of Temperate and Tropical Regions. Land Use. Foley. Lal. E. “Croppers to Livestock Keepers: Livelihood Transitions to 2050 in Africa Due to Climate Change. 2002. S. Larson.1098/rstb. 2 Gibbs. 2008. 2010. N. S. P. doi:10. marginal abatement cost curves and trade-off graphs were used to assess the cost-effectiveness of the technologies in carbon sequestration. R.. K. Sustainable Land Management for Mitigation of and Adaptation to Climate Change. Clark. Robert et al.. Last. “Pathways of Agricultural Expansion Across the Tropics: Implications for Forest Resources.0158. While there are many studies on soil carbon sequestration. and Holmgren. Myers.. Pushparajah. F. and Thornton. A. Martino. 2003. Asia.” Philosophical Tranactions of the Royal Society B 365: 2973–2989. “Soil Carbon Stocks and Land-Use Change: A Meta Analysis. and comprehensive assessments of greenhouse mitigation potentials of SLM practices. Thailand: International Board for Research and Management. Furthermore. 2005. E.” Food Policy 36: S33–S39. Intergovernmental Panel on Climate Change. 2010.. Z. 2011. Chapter 4 reports the estimates from ecosystem simulation. “Soil Erosion and the Global Carbon Budget. Lal. R. REFERENCES Burney. A.. Davis. J. B. D. J. K.. Vol. Land-Use Change. A.. H. “Greenhouse Gas Mitigation in Agriculture.. M. Fourth Assessment Report. and Latin America.2 A meta-analysis was carried out to provide soil carbon sequestration rates in Africa. 2000. Asia.. Chapter 2 provides a brief review of soil organic carbon dynamics and the methods for soil carbon assessment. ed. (2005). Smith. L. while Chapter 5 concludes with the benefits and costs of adopting carbon sequestering practices and a review of evolving funding mechanisms to support climatesmart agriculture in developing countries. 2: Technical Papers. R. and Gifford.. Achard. 2007. D.” Environment International 29: 437–450.” Environmental Science and Policy 12: 427–437. Jones. Bangkok. agro-ecosystems resilience. 1991.. Chapter 3 reports the increase in soil carbon for selected sustainable land management practices in Africa. Ogle. and Pierce. F. the ecosystem simulation modeling technique was used to predict future carbon storage in global cropland soils. Willett. Watson. and Forestry. and Lobell.. Dumanski. P. Cai. The report will provide a broad perspective to natural resource managers and other professionals involved in scaling up CSA.. J. J. and R.” Proceedings of the National Academy of Sciences 107 (38): 16732–16737.4 CH A PTER 1 — INTR OD UC TION 1. Intercontinental Panel on Climate Change (IPCC). Cambridge.

2008. Emissions from land-use change are about 1. while croplands occupy about 11 percent (table 2. climate.1 SOIL ORGANIC CARBON DYNAMICS AND ASSESSMENT METHODS SOIL ORGANIC CARBON DYNAMICS Different ecosystem types store different amounts of carbon depending on their species compositions.grida.1). policy and institutional failures. http://www.aspx. and oceans. The efficiency of oceans and lands as carbon dioxide sinks has declined over the years. Among the biomes. population growth.no/publications/rr/natural-fix/page/3724. Currently. and other biophysical features (figure 2. Rapidly growing emissions are outpacing the growth in natural sinks. relief. EC O N O M I C A N D S E CT OR WORK 5 . Of the estimated over 150 million km2 of terrestrial ecosystems area. and international trade. IGBP-DIS.C H A P T E R 2 — S O I L ORGANIC CARBON DYNAMICS A ND A SS ES S MENT METH OD S Chapter 2: 2. has the highest density of carbon storage. Soils generally hold more carbon than vegetation across biomes and account for 81 percent of terrestrial carbon stock at the global level. The global carbon cycle describes the transfer of carbon in the earth’s atmosphere. 2000. The underlying driving factors of tropical deforestation are highly interconnected and include poverty.2). and natural gas) and land use (table 2. vegetation carbon stocks range from 3 Gt for croplands to 212 Gt for tropical forests. soil types. urban expansion.1: Carbon Stocks in Biomass and Soils Carbon storage in terrestrial ecosystems (Tonnes per ha) 0 to 10 10 to 20 20 to 50 50 to 100 100 to 150 150 to 200 200 to 300 300 to 400 400 to 500 More than 500 Source: Ruesch and Gibbs. The tundra biome.5 Gt C per year. vegetation. oil.1). Source: UNEP/GRID. forests account for more than 40 million km2 (about 28 percent). largely determined by tropical deforestation that exacerbates soil erosion and organic matter decomposition. Savannahs and grasslands both cover about 23 percent. and the attendant demand for natural resources. covering an area of less than 10 million km2. soils. while soil carbon stocks range from 100 Gt for temperate forests to 471 Gt for boreal forests. FIGURE 2. natural sinks remove an average of 55 percent of all anthropogenic carbon dioxide emissions. which is slightly lower than 60 percent they removed some 50 years ago (Global Carbon Project 2009). The two most important anthropogenic processes responsible for the release of carbon dioxide into the atmosphere are burning of fossil fuels (coal.

5 15 6.5 9 3.4 ± 1.7 121 95. vegetation.1 4.5 8 4. Out of this.550 Gt.0 304 Deserts 45. the C fixed in the atmosphere becomes soil carbon through the process of above.3 ± 0.2 ± 0. Over time. release of sap exudates from plant roots into the soil.8 240 3 2.7 ± 1. and oceans. Different fractions or soil organic carbon pools have different functions within the soil system.6 ± 0.4 ± 0.6 −1.4 −2.3 559 Tropical savannas 22.3 127 Wetlands 3.5 216 50.5 66 20.0 Sources: IPCC (2007) and the Global Carbon Project (2009).5 Net land-to-atmosphere flux −0.4 59 37.7 1.011 2.2 ± 0. and carbon bound to soil minerals.5 428 Temperate forests 10.8 −2. while the soil inorganic carbon and elemental pools make up the remaining 950 Gt (Batjes 1996). Globally.3 6.5 6 4. NPP) useful for growth and energy storage.7 −1.9 159 Boreal forests 13.1: Carbon Stocks in Vegetation and Top 1 Meter of Soils of World Biomes BIOMES Tropical forests CARBON STOCKS (Gt C) AND PROPORTION IN THE ECOSYSTEM (%) AREA (MILLION km2) VEGETATION PROPORTION (%) SOILS PROPORTION (%) TOTAL 17.2 ± 0.9 −1.0 ± 0. energy for biological processes.0 295 97.477 19 81 100 Proportion (%) Source: Based on Watson et al.4 ± 0.2: Global Carbon Budget (Gt C) SOURCE 1980s 1990s 2000–2008 Atmospheric increase 3.0 199 Tundra 9.6 212 49. and root die-off. and provision of nutrients for plants. A more stable fraction.7 131 Croplands Total 16 151. improve water and nutrient retention.3 128 97.6 CHAPTER 2 — S OIL OR GA NIC CA R B ON D YNA MIC S A ND A SS ES S MENT M ETH OD S TABLE 2.1 100 62.9 −2.0 264 80.0 191 96.6 ± 0.3 ± 0. The elemental and inorganic forms of soil carbon primarily result from mineral weathering and are less responsive to land management than soil organic carbon (table 2. These compounds originate from the photosynthetic activities of plants. Through photosynthesis. CARBON SEQUESTRATION IN AGRICULTURAL SOILS .and below-ground decomposition of materials. the soil carbon pool (also referred to as the pedologic pool) is estimated at 2.4 ± 0. The soil carbon pool is more than three times the size of the atmospheric pool (760 Gt) and about 4. the soil organic carbon pool comprises 1. (2000) and Ravindranath and Ostwald (2008). and increase crop yields (Kell 2011).3 Net ocean-to-atmosphere flux −1. improve soil structure.0 1. Breeding crop plants with deeper and bushy root ecosystems could simultaneously sequester more carbon.3 225 93.8 ± 0. Crop residues are readily broken down and serve as substrates to soil microorganisms. Particulate organic carbon is broken down relatively quickly but more slowly than other crop residues and is important for soil structure. Soils are critically important in determining global carbon cycle dynamics because they serve as the link between the atmosphere.500 Gt up to 2 meters deep.2 466 2.3 ± 0. TABLE 2.7 Partitioned as: Land-use change flux Residual land sink 1. microbial organisms.1 Fossil fuel emissions 5.3 ± 0.4 7.1 3.7 ± 1.7 −2.7 471 84.7 88 15.5 times the size of the biotic pool (560 Gt).3). plants reduce carbon from its oxidized form to organic forms (net primary productivity. Soil organic carbon is a complex mixture of organic compounds composed of decomposing plant tissue.0 330 Temperate grasslands 12.1 ± 0.

2. humus..05 mm that are dominated by molecules attached to soil minerals Source: Synthesized from Schumacher (2002).000.05 and 2 mm humus. the highly stable. with size between 0. In the tropics. inceptisols. histosols.g. usually as carbonates—that is. CaMg(CO3)2 and. siderite (Fe CO3) Agricultural inputs such as liming can also introduce calcite and dolomite into the soil. Some very stable humus complexes can remain in the soil for centuries or millennia. and soot) Dispersion of these carbon forms during mining Inorganic Geologic or soil parent materials. ultisols. and inceptisols (figure 2. highly decomposed materials less than 0.4. At the global level. calcite.7 C H A P T E R 2 — S O I L ORGANIC CARBON DYNAMICS A ND A SS ES S MENT METH OD S TABLE 2.2: Global Soil Regions Robinson projection scale 1:130.000 Soil orders Alfisols Entisols Inceptisols Spodosols Rocky land Andisols Gelisols Mollisols Ultisols Shifting sand Aridisols Histosols Oxisols Vertisols Ice/glacier Source: United States Department of Agriculture. can be classified into two depending on the level of decomposability: The first is active humus that is still subject to further decomposition. alfisols. FIGURE 2. also referred to as particulate organic carbon. and the other is passive humus (or recalcitrant carbon). insoluble form that is not subject to further decomposition. and box 2.3: Forms of Carbon in the Soil FORMS SOURCES Elemental Geologic materials (e. Organic Plant and animal materials at various stages of decomposition ranging from crop residues with size of 2 mm or more Plant debris.1). the soil organic carbon pool is concentrated in five major soil orders: histosols. entisols. to some extent. the largest amount of soil organic carbon is found in oxisols. graphite. water retention. graphite and coal) Incomplete combustion of organic materials (e. charcoal. CaCO3 dolomite. Active humus is an excellent source of plant nutrients (nitrates and phosphates). while passive humus is important for soil physical structure.. and tilth.g. and oxisols. EC O N O M I C A N D S E CT OR WORK . table 2.

tillage operations.6 234 0.2 85 16. and drainage of peat lands) is between 0. soil erosion accounts for up to 1. This is more than 50 percent of the carbon absorbed by land. However.287 2.4 29 5.5 40 0. corresponding to carbon emissions of 0.2).2 119 23.2 60 11. NPP—the rate of photosynthesis minus autotrophic respiration—is the major factor influencing attainable sequestration and is modified by above-ground versus below-ground allocation. and drainage. The actual carbon sequestration is determined by land management factors that reduce carbon storage such as The current rate of carbon loss due to land-use change (deforestation) and related land change processes (erosion. The amount changes over time depending on photosynthetic C added and the rate of its decay.4 47 9. (1993).9 1. South America.8 CHAPTER 2 — S OIL OR GA NIC CA R B ON D YNA MIC S A ND A SS ES S MENT M ETH OD S TABLE 2. Such factors include soil texture and clay mineralogy.4 19 1.7 2 0. excessive fertilizers. Under undisturbed natural conditions.1 6.8 Inceptisols 21. Globally.6 100 19.6 19 3.44 Gt per year (table 2. This is more than 57 percent CARBON SEQUESTRATION IN AGRICULTURAL SOILS .669 100 506 100 Source: Eswaran et al. bulk density.330 8. the potential soil carbon sequestration capacity is equivalent to the cumulative historical carbon loss. Soil erosion is the major land degradation process that emits soil carbon. tillage. The degree of loss is higher in soils that are susceptible to accelerated erosion and other soil degradation processes.644 5.117 18.4 11.9 Andisols 2.7 119 7. organic matter decomposition.552 1.4 Ultisols 11.512 23.6 11.7 Entisols 14.4: Soil Carbon Pool up to 1-M Deep for Soil Orders of the World’s Ice-Free Land Surface GLOBAL LAND AREA SOIL ORDER EXTENT (1000 km2) PROPORTION (%) SOIL ORGANIC CARBON POOL (Gt) TROPICAL LAND AREA PROPORTION (%) EXTENT (1000 km2) PROPORTION (%) SOIL ORGANIC CARBON POOL (Gt) PROPORTION (%) Alfisols 18. biomass burning.743 23.9 30 5.2 Others 7.683 3.1 72 4.1). Theoretically.3 4.7 9. and leaching.7 and 2. erosion.480 4.018 18. The decomposition rate increases with temperature but decreases with increasingly anaerobic conditions.8 Histosols 1.3 Aridisols 31.921 11 148 9.2 Gt of C emitted to the atmosphere each year.16 to 0. The annual soil losses in Africa.565 9.4 11 2.5).215 1.5 4.283 13.411 12.358 2.7 286 0.5 127 8.7 18 1.5 110 7 9.772 8. box 2. The soil organic carbon pool represents a dynamic balance between gains and losses.1 2 0. residue removal. depth. residue removal.2 2.878 3. aeration.189 4.8 Vertisols 3.3).576 100 49.4 3.4 105 6.256 6. The conversion of natural vegetation to agricultural ecosystems leads to a depletion of the soil organic carbon pool by as much as 60 percent in the temperate regions and by 75 percent or more in the tropics (box 2.6 71 4.9 78 4.1 1. and Asia are estimated at 39 to 74 Gt. The attainable carbon sequestration is set by factors that limit the input of carbon to the soil system.9 Mollisols 5.2). Climate has both direct and indirect effects on attainable sequestration.1 Gt carbon per year (table 2.580 352 22. inputs of carbon from litter fall and root biomass are cycled by output through erosion. and proportion of coarse fragments (figure 2. only 50 to 66 percent of this capacity is attainable through the adoption of sustainable land management practices (Lal 2004.4 Oxisols Spodosols Total 135.745 357 22.3 16 100 1.5 2 0. Land management practices that increase carbon input through increasing NPP tend to increase the attainable level to nearer the potential level. The potential carbon sequestration is controlled primarily by pedological factors that set the physico-chemical maximum limit to storage of carbon in the soil.

Source: Modified from United States Department of Agriculture. Included in this category are partially developed soils of the Sahel region of West Africa. Aridisols: Formed under arid climates. Soil respiration. inceptisols are formed on recent geomorphic surfaces in semi-arid to humid environments. but they are difficult to till. Spodosols: Commonly occurring in areas of coarse-textured deposits of humid regions. oxisols are highly weathered soils of tropical and subtropical regions. Thus. histosols have a high content of organic matter and no permafrost.1: Brief Description of Soil Orders Alfisols: Formed primarily under forest or mixed vegetative cover. They are found on stable landscapes. a small change in soil respiration can significantly alter the balance of atmospheric carbon dioxide concentration compared to soil carbon stores. mucks. Gelisols are not highly fertile because nutrients are very easily leached above the permafrost. Entisols: Occurring in areas of recently deposited parent materials or areas where erosion or deposition rates exceed the rate of soil development. flood plains. They are commonly called peats. alfisols result from weathering processes that leach clay minerals from the surface to the subhorizon. entisols are characterized with little or no horizon development. or sand dunes. relatively high organic matter. spodosols have developed from weathering processes that strip organic matter and iron and aluminum oxides from the surface to the subsoil. Andisols: Common in cool areas with moderate to high precipitations. Gelisols: Found mostly in very cold areas under the influence of glaciation. mollisols are grassland soils with dark-colored surface horizons. It is about 60 times the annual contribution of land-use change and about 11 times that of fossil fuel to atmospheric emissions. the terrestrial carbon pool assimilates 120 Gt C from the atmosphere in the form of gross primary productivity (or photosynthesis). Inceptisols: Exhibiting modest soil weathering and horizon development. of the emission through land-use change and underscores the need for carbon conservation through zero tolerance for soil erosion. Spodosols tend to be acidic and are inherently infertile. have low natural fertility. High amounts of soil organic matter accumulate in the upper layer. Soil respiration is regulated by several factors including temperature. gelisols are characterized by permafrost within 2 m of the soil surface. Ultisols: Formed from fairly intense weathering and leaching that results in clay accumulation at the subsoil. Oxisols: Dominated by low activity minerals. droughts. or impeded drainage.C H A P T E R 2 — S O I L ORGANIC CARBON DYNAMICS A ND A SS ES S MENT METH OD S BOX 2. ultisols are typically acidic with most nutrients concentrated in the topsoil. 9 . Each year. Vertisols: Dominated by high content of swelling and shrinking clay minerals. the flux of microbially and plant-respired carbon dioxide (CO2) from the soil surface EC O N O M I C A N D S E CT OR WORK to the atmosphere. Vertisols tend to be high in natural fertility. some soils of the riverine floodplains of the Ganges and Brahmaputra Rivers in Bangladesh and India. They have moderately low capacity to retain fertilizer and soil amendments. andisols result from weathering processes that generate minerals with little orderly crystalline structure (volcanic glass) and usually have high nutrientand water-holding capacity. Most histosols are saturated all the year round. estimated at 75 to 100 Gt C per year is the next largest terrestrial carbon flux (Raich and Potter 1995). the lack of moisture markedly restricts the intensity of weathering and development of aridisols. and low capacity to retain fertilizer and soil amendments. making most gelisols black or dark brown in color. Histosols: Formed in decomposed organic materials that accumulate faster than they decay. and the floodplains of Southeast Asia. or moors. The paucity of vegetation also leads to low organic matter content. Mollisols: Formed under moderate to pronounced seasonal moisture deficits. vertisols typically form from highly basic rocks in climates that are seasonally humid or subject to erratic floods. They occur in many environments such as on steep slopes. and high base saturation. bogs.

TABLE 2.8–1.4 0.0 1.6–0.8 0.16–0.8–1.3: Factors Affecting Soil Carbon Sequestration Potential Defining factors: – Mineralogy/content – Depth – Stoniness – Bulk density – Aeration Attainable Limiting factors: – NPP and allocation – Climate (direct) – Climate (via NPP) Reducing factors: – Erosion – Tillage – Residue removal – Disrupted biology – Drainage SOC-increasing measures Actual SOC-protecting measures SOC level (t1/2 ≥ 10 years) ton ha–1 Source: Redrawn from Ingram and Fernandes (2001).5–2. Variations in temperature are significantly and positively correlated with changes in global soil respiration (Bond-Lamberty and Thompson 2010).04–0.08 7.16 Europe 13.2–0. the global soil respiration reached roughly 98 Gt.2 0.0–6. Gt C/YEAR) EMISSION (20 PERCENT OF DISPLACED SOIL CARBON.24 North America 28.6 0. about 10 CARBON SEQUESTRATION IN AGRICULTURAL SOILS .9 0.10 CHAPTER 2 — S OIL OR GA NIC CA R B ON D YNA MIC S A ND A SS ES S MENT M ETH OD S carbon sequestration situation FIGURE 2.2 0.30–0.1 0.44 South America 39.2 0. In 2008.2 Oceania Total Source: Adapted from Lal (2003). moisture. and level of aeration of the soil.1–0. Climate change is positively correlated with increasing rate of soil respiration.24 Asia 74.0 0.16–0.1 0.12–0.4 0. nitrogen content.8–1. vegetation type.02–0.5: Estimate of Erosion-Induced Carbon Emission CONTINENT GROSS EROSION (X 109 Mg/YEAR) SOIL CARBON DISPLACED BY EROSION (2 TO 3 PERCENT OF SEDIMENT.2 0.04 201. Gt C/YEAR) Africa 38.1 4. Higher temperatures trigger microbes to speed up their consumption of plant residues and other organic matter.

Sulaeman. This huge drop was mostly due to the high conversion of forests and natural vegetation into plantations and subsequently to food crops. Global Change Biology 17:1917–1924. Since the late 1960s. An analysis over the period from 1930 to 2010 revealed that human activities are more important than environmental factors in explaining soil organic carbon trend.. Between 1930 and 1950. and animal manure application were mostly responsible for the increase in soil organic carbon stock. From the Japanese occupation in 1942. and enhance ecosystem services supply from the soil. throughout its independence years. between 1960 and 1970.B. increased soil carbon sequestration. The increased biomass and the return of crop residues. 2010. However.C H A P T E R 2 — S O I L ORGANIC CARBON DYNAMICS A ND A SS ES S MENT METH OD S BOX 2. Further intensification has resulted in improved environmental awareness. and McBrateney A. and coffee. improve soil quality. 2010).026 persons km−2. and until the early 1960s. Java is undoubtedly the most densely populated and the most intensively cultivated island in Indonesia.4 t ha−1 between 1930 and 1940 to 7. During the Dutch colonial period. most land development was for plantations such as tea. rubber. 25 20 t ha–1 15 10 5 0 1930–1940 1940–1950 1950–1960 1960–1970 1970–1980 1980–1990 1990–2000 2000–2010 Source: Minasny. B. and increased resilience of the agricultural system. The Green Revolution of the 1960s saw Java producing close to two-thirds of the country’s rice. As a result. Y. Is soil carbon disappearing? The dynamics of soil organic carbon in Java.2: Sustainable Land Management Practices Reverse Soil Carbon Loss in Java Research in the tropics has demonstrated the decline of soil organic carbon by as much as 60 percent after conversion of forest to cropland.. EC O N O M I C A N D S E CT OR WORK 11 . Indonesia faced a serious problem of food scarcity. decline in soil carbon stock was primarily due to conversion of forests to cropland. soil organic carbon markedly declined by 62 percent of its natural condition. sustainable land management practices can accumulate soil organic carbon. including the use of highyielding varieties and chemical inputs. By the 1990s. increased likelihood of adoption of sustainable land management practices. green compost. With an estimated population density of 1.3 t ha−1 between 1960 and 1970 (see figure below). The median soil organic carbon stock in the topsoil dropped from 20. Some soil scientists have recently used legacy soil survey data to capture the long-term trend of soil organic carbon in Java in Indonesia (Minasny et al. soil organic carbon stock had risen to about 11 t ha−1 as there was also a large interest in organic farming in Java. reverse chronic soil degradation. soil organic C has increased slightly as a result of the government extension program to disseminate new agricultural production knowledge among farmers.

3. and provisioning ecosystem services. ƒ Changes in soil carbon stocks can help track changes in regulating. Forest inventory that relates tree diameters or volume to forest carbon stocks using allometric relationships.1 Gt C per year between 1989 and 2008. and 2. and litter—and the soil organic carbon pool. 1. and water management can optimize soil respiration in addition to improving soil carbon. The assessment can be undertaken either at national or project level. but effort is required to ensure that the methods are comparable. crop rotations. Carbon assessment for land management projects can be either purposely for climate mitigation or for nonclimate mitigation. Mitigation projects involve estimation of verifiable changes in carbon stocks over a given period in the defined project area and require methods for estimating carbon stocks and changes for the baseline scenario (without the project) and the project. application of manure. Carbon assessment for land management projects not principally designed for climate change mitigation is carried out for a number of reasons: ƒ The need to assess the carbon footprint of the operational work of funding agencies (see section 2. The assessment covers four biomass pools—above ground. use of cover crops (green manure). measurement techniques. dead wood.12 CHAPTER 2 — S OIL OR GA NIC CA R B ON D YNA MIC S A ND A SS ES S MENT M ETH OD S times more carbon than humans release into the atmosphere each year. 2. Conventional tillage leads to the destruction of soil aggregates. Soil carbon assessment in different parts of the world requires methods that are appropriate to the circumstances. conservation tillage. ƒ Changes in soil carbon over the lifetime of a project are an indicator of the success of SLM intervention.4). Soil respiration increased 0. Estimating the gain in carbon stock for each pool due to accumulation or losses and calculating the difference between gains and losses as net emissions or removal (a gain-loss approach). credible CARBON SEQUESTRATION IN AGRICULTURAL SOILS . Tillage operations can significantly affect soil respiration. below ground. The key steps involved are as follows: Typically.3 TECHNIQUES OF SOIL CARBON ASSESSMENT Methods to assess above-ground biomass are more advanced than for soil carbon. Furthermore. though this is hardly a prime objective.6. for carbon projects. different countries adapt the Intergovernmental Panel on Climate Change (IPCC) guideline for national GHG by using sampling methods. and soil organic matter decomposition. excessive respiration. Signatory parties of the UN Framework Convention on Climate Change (UNFCCC) are required to prepare national GHG inventories on a periodic basis and report them to the body. use of deep-rooted crops. The key differences for carbon assessment for the two types of projects are summarized in table 2. ƒ Interest in benefiting from carbon finance. Use of optical. Annex I or industrialized countries are required to estimate and report emissions and removals annually. supporting. When other factors are at optimum. while non-Annex I or developing countries only need to report every 3 to 5 years. A rise in temperature by 2°C is estimated to release an additional 10 Gt C per year to the atmosphere through soil respiration (Friedlingstein et al. Estimating the area under a given land-use category in a given year and the area under each category subjected to land-use change 2. The three major methods for above-ground carbon assessment include the following (Gibbs et al. Biome averages involving the estimation of average forest carbon stocks for broad forest categories based on a variety of input data sources. leading to reduced crop production and decreased resilience of the soil ecosystem. Excessive application of large amounts of nitrogenous fertilizer can markedly increase root biomass and stimulate soil respiration rates. 2. and models tailored to their particular circumstances. Estimating the stocks of carbon in each pool at the beginning and end of the period to calculate net emissions or removal (stock difference approach) 3. 2003). 2007): 1. radar.2 CARBON ASSESSMENT FOR LAND MANAGEMENT PROJECTS Carbon assessment entails the estimation of stocks and fluxes of carbon from different land-use systems in a given area over a period of time. or laser remote-sensing data integrated with allometry and ground measurements. Many different methods have been tested in a number of countries.

is quite laborious and very expensive.7 has unique constraints related to costs.6: Comparison of Carbon Assessment for Carbon Mitigation and Non-Carbon-Mitigation Projects PROJECT PHASE Conceptualization Proposal development CARBON MITIGATION PROJECTS NONCARBON-MITIGATION PROJECTS (SUSTAINABLE LAND MANAGEMENT INCLUDING FOREST. The degree and nature of sampling depend on the carbon assessment objective. CROPLAND MANAGEMENT) Primary focus: carbon mitigation and carbon credits—global environmental benefit Primary focus: forest and biodiversity conservation. Most assessments typically involve a combination of these techniques. and sampling design requirements and associated levels of bias or uncertainty. a Project boundary refers to the physical boundary of the land area delineated either with a geographical information system or a global positioning system and the greenhouse gas boundary that includes all fluxes of all gases affected by project activity. The most established type of direct soil carbon assessment entails collecting soil samples in the field and analyzing them in the laboratory by combustion techniques. whether for national or regional accounting or for carbon offset project.8. geographic scope. A comparison of these techniques is provided in table 2.7). two measurements for a minimum of 3. b Carbon assessment methodologies are the blueprints to design. and operate carbon projects.000 plots are needed to detect an expected change of 11 g C m−2 yr−1 in the organic layer of upland forest soils at 10-year sampling intervals. biodiversity conservation. Each context will require a differing degree of granularity and measurement set to assess uncertainty in the estimates. and the use of biogeochemical models. use of in situ analytical methods. One round of measurement was estimated to cost about 4 million. well-defined plan is required for monitoring of local environmental and socioeconomic impacts Project review and appraisal Baseline and project scenario carbon monitoring methods are critical Monitoring plan for local environmental and socioeconomic benefits is important Implementation Activities aimed at maximizing carbon benefits. and livelihoods enhancement Secondary focus: soil and biodiversity conservation Cobenefits: carbon mitigation is implicit though often not mentioned in proposal Clear historical records of the past vegetation and soil carbon status are required Historical vegetation status not so critical to project eligibility Project boundarya impacted by project activities needs clear definition Project boundary needed for estimating environmental and socioeconomic benefits restricted to project area Estimation of baseline carbon stocks is crucial as well as rigorous plan for monitoring carbon stock changes Baseline economic benefits. The exception is infrared spectroscopy currently being 13 . corresponding to 8 percent of the value of the annual sequestration of about 3 million tCO2 of Finland’s upland forest soils. They document the protocol for quantifying carbon emissions and removals and include guidelines for identifying baseline scenario and assessing additionality in all carbon pools relevant to the project. Several in situ soil carbon analytical methods are being developed with the objective of offering increased accuracy. though more precise and accurate. precision.C H A P T E R 2 — S O I L ORGANIC CARBON DYNAMICS A ND A SS ES S MENT METH OD S TABLE 2. verify. Soil carbon assessment methods can be broadly classified into direct and indirect methods depending on whether carbon content in soil samples is directly measured or inferred through a proxy variable (table 2. At the national level. The direct method. and biodiversity need to be clearly identified. pooled sampling. watershed protection. but it can be addressed with appropriate design that accounts for soil spatial variation. The precision obtained with such sampling corresponds to detection of soil carbon change greater than 860 g C m−2. followed by other cobenefits Activities are aimed at maximizing biomass production. Most of the in situ techniques are still in their infancy. EC O N O M I C A N D S E CT OR WORK In Finland. inadequacies. Field sampling is technically challenging. crop yields. GRASSLAND. Makipaa et al. (2008) observed that organic layer carbon measurements cost 520 per plot if 10 samples are analyzed. Strategies to reduce the cost of soil carbon monitoring include lengthening the sampling interval. Each of the methods depicted in table 2. increasing the efficiency of sampling through stratification. Additionality must be demonstrated Project-specific methodology is used All the relevant carbon pools must be considered Large transaction cost likely for carbon inventory and monitoring Additionality of local environmental and socioeconomic benefits are critical Soil carbon critical for land development projects due to effects on agricultural sustainability Moderate transaction cost for monitoring Source: Modified from Ravindranath and Ostwald (2008). and livelihood improvement Monitoring and evaluation Approved methodologiesb are crucial. and cost-effectiveness over conventional ex situ methods. and cost-effective techniques of monitoring changes in soil carbon are required. soil fertility. Also.

Costs are prohibitive on per project basis 1 Rapid.1 Very fast—provides total soil carbon measurements in seconds. currently. low cost. and scanner must be adapted to capture large areas 10 100.8: Characteristics of Emerging In Situ Methods of Soil Carbon Analytical Techniques DIRECT METHOD TYPE OF RADIATION MEASURED PROCESS PENETRATION DEPTH (CM) Mid-infrared spectroscopy Molecular/diffuse reflectance Infrared 1 Near-infrared spectroscopy Molecular/diffuse reflectance Near infrared 0.000 Source: Adapted from Chatterjee and Lal (2009). Field sampling and laboratory measurements using dry combustion or wet combustion Accounting techniques  Stratified accounting with database  Remote sensing to infer factors determining above-ground carbon inputs 2.7: Direct and Indirect Methods of Soil Carbon Assessment DIRECT METHODS INDIRECT METHODS 1.1 Inelastic neutron scattering Nuclear/neutroninduced nuclear reactions Gamma rays 30 SAMPLED VOLUME (CM3) ADVANTAGES DISADVANTAGES In situ–based measurement of carbon.  RothC  Century  DNDC  PROCOMAP  CO2FIX 3. capable of spectrally resolving several elements apart from carbon Interference with iron compounds around 248 nm wavelength. Better than near infrared in distinguishing soil organic from inorganic carbon.2 Laser-induced breakdown spectroscopy Atomic/ plasma-induced emission Visible 0. Emerging technologies for in situ determination  Laser-Induced Breakdown Spectroscopy  Inelastic Neutron Scattering (still being assessed for improved reliability for measurement)  Near-infrared and mid-infrared spectroscopy Source: Modified from Post et al. flux tower measurements Biogeochemical/ecosystem simulation modeling to understand below-ground biological processes. Eddy covariance. CARBON SEQUESTRATION IN AGRICULTURAL SOILS . for example. TABLE 2.14 CHAPTER 2 — S OIL OR GA NIC CA R B ON D YNA MIC S A ND A SS ES S MENT M ETH OD S TABLE 2. the technology cannot directly distinguish soil inorganic from organic carbon Large footprint of about 2 m2 and sampling depth The technology is still at its infancy and needs to be calibrated for wide variety of soil types. in situ method Less accurate than mid-infrared in predicting soil organic carbon 0. (2001).

and initial soil carbon. crop yield.net/sites/default/ files/ICRAF-ISRICSoilVNIRSpectralLibrary. commercial crop yield. temperature. pH. phosphorus. and carbon in plant residue CO2FIX Simulates carbon dynamics of single/multiple species. Progress is being made in developing and testing cost-effective soil carbon monitoring methods. monthly open pan evaporation. and sulfur levels Total carbon.15 C H A P T E R 2 — S O I L ORGANIC CARBON DYNAMICS A ND A SS ES S MENT METH OD S used to develop a spectral library for soils of the world. Indirect estimation of soil organic carbon changes over large areas using simulation models is increasingly important to fill knowledge gaps about the biogeochemical processes of soil carbon sequestration. precipitation. nitrogen leaching. and they are particularly useful for up-scaling site-specific information to the regional level. ammonia (NH3). fluxes of gases including N2O. spatially explicit biogeochemical modeling. nitric oxide NO. and methane CH4 Source: This study. bulk density. nitrogen. deadwood.org/climatechange/carbon-benefits/ . they are particularly useful in the context of developing countries where land resources data are scarce. wood density.9 compares the features of some of the biogeochemical models commonly used for soil carbon assessment. and an estimate of the organic input Total organic carbon content and carbon content in microbial biomass PROCOMAP Equilibrium model for estimating carbon stocks Activity data. P. and emissions of nitrous oxide (N2O). cost-effective methods of quantifying the carbon benefits of sustainable land management projects. ISRIC-World Soil Information: A globally distributed soil spectral library: visible near-infrared diffuse reflectance spectra. planting rate. plant N. average monthly mean air temperature. and length of growing period Carbon stocks and fluxes. methane (CH4). above. yield tables. and management conditions. rainfall.4 TABLE 2.11. soil temperature and moisture regimes. carbon dioxide. and mean annual increment in biomass and soil Biomass and soil carbon stock. phosphorus. incremental carbon stocks. crop rotation timing and type. maximum biomass in stand.unep. Table 2. 1999). total biomass and soil carbon. Examples of national carbon accounting system and tools are presented in table 2. inorganic fertilizer timing. The Global Environment Facility (GEF) in collaboration with other partners is currently implementing the Carbon Benefits Project (CBP) to develop standardized. Monitoring and verifying soil carbon sequestration at the project or regional scale require five components (Post et al. dinitrogen (N2). Simulation models describe changes in soil organic carbon under varying climate. and sulfur for different ecosystems Monthly mean maximum and minimum air temperature and total precipitation. nitrogen. and carbon dioxide (CO2) Plant growth data. carbon sequestration. residue incorporation timing and amount. total nitrogen. total dry matter. and scaling-up the results to the entire project area (table 2. soil clay. and cost-effectiveness indicators DNDC DeNitrification-DeComposition is used for predicting crop growth. Though the models could have limited accuracy. Models provide a cost-effective means of estimating GHG emissions in space and time under a wide range of biophysical and agricultural management conditions. carbon input into soil. development of measurement protocols.africasoils. Monitoring the trends in soil carbon over a large geographical area through repeated sampling is mainly restricted to developed and few developing countries. nitric oxide (NO). rotation period. irrigation timing and amount. and S content.and below-ground biomass. These include the selection of landscape units suitable for monitoring soil carbon changes. soil water dynamics. air temperature. soil texture. forests. application of remote sensing to estimate soil organic carbon controlling parameters. and litter and soil organic carbon production RothC Estimation of turnover of organic carbon in topsoil Clay. atmospheric nitrogen decomposition rate. soil water dynamics. http://www.9).3 The spectral library provides a valuable resource for rapid characterization of soil properties for soil quality monitoring and other agricultural applications. atmospheric and soil nitrogen inputs. and agroforestry systems Simulation length. carbon content. EC O N O M I C A N D S E CT OR WORK 4 http://www. 3 World Agroforestry Centre. soil. biomass carbon. and tillage timing and type Total carbon. monthly rainfall.pdf.9: Comparative Features of Some Carbon Estimation Models MODEL FEATURES KEY INPUTS KEY OUTPUTS CENTURY Simulates long-term dynamics of carbon. initial carbon. NH3. amount and type. vegetation carbon stocks.

management history.and subnational-scale soil carbon stock variations in developing countries using RothC and Century models (table 2. Voluntary Reporting of Greenhouse Gases-Carbon Management Evaluation Tool (http://www.10: Components of Soil Carbon Monitoring at the Regional Scale COMPONENTS DESCRIPTION Selection of landscape units The selection will depend on responsiveness of the area to land management practices as determined by climate. Multitemporal moderate resolution remote sensing such as Landsat Thematic Mapper and Moderate Resolution Imaging Spectroradiometer can provide information such as land-use and land cover change.climatechange. http://www. 2009) Biogeochemical modeling Models are used to determine soil carbon changes over large areas because satellites cannot sense below-ground biological processes. enteric methane emissions. rice methane emissions. Application of remote sensing Remote sensing can provide information on net primary productivity. and nitrous oxide emissions. colostate. farmer organizations. and soil moisture that can markedly improve up-scaling of soil carbon assessment. maps of soil type and soil carbon. or several land management practices Up-scaling Scaling-up to large areas requires integration from a variety of sources including field measurements. other ancillary field measurements. http://www. geographical information system.gc.shtml Source: This study. models. land-use change. and ecosystem modeling—the Full Carbon Accounting Model. The software accommodates Tier 1 and 2 methods as defined by the Intercontinental Panel on Climate Change. Source: Synthesized from Post et al. http://carbon. and the data program. CARBON SEQUESTRATION IN AGRICULTURAL SOILS . and remote sensing.edu/projects/ghgtool/software. temperature. Development of protocol Changes in soil carbon can generally be estimated as changes in stocks (from direct measurement) or fluxes (using eddy covariance methods) (see table 2. and humidity. and soils was developed for the Ministry of the Environment by Landcare Research and Scion. multiple land uses. laboratory analyses.cometvr. Canada (NFCMARS) NFCMARS is designed to estimate past changes in forest carbon stocks and to predict. cellulose absorption index derived from remote imaging spectroscopy has been used to infer tillage intensity and residue quantity (Serbin et al. Since its initial development in 1973. manure methane. and changes in land management over time. and the GEF Soil Organic Carbon System that approximates national. changes in carbon stocks in the next two to three decades.at/carboinvent/workshop/1000_Peter_Stephens_ver_final.7).edu/). and location and amount of crop residue for input into models. and availability of historical data. Models are useful for understanding soil properties–land management interactions and for predicting soil carbon sequestration. United States The Forest Vegetation Simulator (FVS) is a family of forest growth simulation models. It allows compilers to integrate global information system spatial data along with national statistics on agriculture and forestry and is designed to produce a consistent and complete representation of land use for inventory assessment. The basic FVS model structure has been calibrated to unique geographic areas to produce individual FVS variants.pdf New Zealand’s Carbon Accounting System The National Carbon Accounting System for New Zealand’s indigenous forest. The CBP comprises a national GHG inventory tool.us/fmsc/fvs/description/index. Accounting and Reporting System.html Agriculture and Land Use National Greenhouse Gas Inventory Software (Colorado State University. it has become a system of highly integrated analytical tools. sampling depth and volume. monthly maps of climate information. The three major activities linked are the remote sensing program.11: Carbon Accounting Systems and Tools NAME DESCRIPTION AND INTERNET LOCATION Australia’s National Carbon Accounting System (NCAS) NCAS estimates emissions through a system that combines satellite images to monitor land use and land-use change across Australia that are updated annually.16 CHAPTER 2 — S OIL OR GA NIC CA R B ON D YNA MIC S A ND A SS ES S MENT M ETH OD S TABLE 2. the modeling and measurement program for GHG accounting and reporting. crop yields.br/geoforest/pdf/group2/04%20-%20National%20carbon%20accounting%20system%20of%20Indonesia.cfs.php National Carbon Accounting System of Indonesia Provides monitoring capabilities for greenhouse gas (GHG) emissions/sinks to establish a credible reference emission level. It can be used to estimate emissions and removals associated with biomass C stocks. existing database. such as rainfall. They can simulate full ecosystem–level carbon balance. Protocols for temporally repeated measurements at fixed locations will generally include stratification and selection of sampling sites. as well as non-CO2 GHG emissions from biomass burning.9).joanneum. 1999. soil properties.au/government/initiatives/national-carbon-accounting. soil C stocks. It monitors forest definition.nrel. leaf area index.nrcan. tillage practices. land management. http://www. United States) The program supports countries’ efforts to understand current emission trends and the influence of land-use and management alternatives on future emissions.colostate. crop rotations. databases containing information on plant species.ca/index_e. Recently. and reporting methods. shrub land. the Agriculture and Land Use Tool (table 2.inpe.pdf Forest Vegetation Simulator. The new suite of tools estimate and model carbon and other GHG flows under present and alternative management and measures.dpi. http://www. forest inventory and modeling. TABLE 2. soil nitrous oxide emissions. and other stakeholders can be of help in selecting pilot areas and the extent to which the results can be extrapolated over the region.fs. They also monitor changes in carbon under specified land use and management. http://www.fed.11). and estimation of the marginal cost of carbon sequestration.gov. based on scenarios of future disturbance rates and management actions. measurement of bulk density.aspx National Forest Carbon Monitoring. Participation of local agronomists.

Chatterjee. inputs. A. Guidelines for National Greenhouse Gas Inventories Vol. 2009. supplemented by other existing methodologies and reviews of default coefficients.org/sites/ v-c-s. 1996. Fourth Assessment Report. it is cost-effective and requires a minimum amount of data. N. Guidelines for National Greenhouse Gas Inventories Vol. Ingram. The methodology.. 1996. R. O. and duration of the project) ƒ Identification of changes in land use and technologies foreseen by project components using specific “modules” (deforestation. A. No. “Monitoring and Estimating Tropical Forest Carbon Stocks: Making REDD a Reality. EX-ACT was developed following the IPCC guideline for national GHG inventory (IPCC 2006).. “Total Carbon and Nitrogen in the Soils of the World. livestock. The BioCarbon Fund of the World Bank has recently developed a carbon accounting methodology to encourage adoption of sustainable land management practices by small-scale Kell. 104: 270–277. 2007.. While EX-ACT primarily works at the project level.0. S.. H. EX-ACT can provide ex ante assessments of the impact of agriculture and related forestry.or. http://www. The methodology currently being applied in the first African soil carbon project allows small-holder farmers in Kenya to access the carbon market and receive additional carbon revenue streams through the adoption of productivity-enhancing practices and technologies. forest degradation.” European Journal of Soil Science 47: 151–163. climate and soil characteristics. 2010. E. Brown. SALM is applicable to projects that introduce sustainable land management practices into croplands subject to conditions such that soil organic carbon would remain constant or decrease with time in the absence of the project. grasslands.. fisheries.. van den Berg. ad hoc coefficients.pdf). C. provides protocol for quantifying carbon emissions and removals and includes guidelines for identifying baseline scenario and assessing additionality in all carbon pools relevant to sustainable land management projects. http://www. J. 2003. Intergovernmental Panel on Climate Change. Reich. 2001. REFERENCES Batjes. “On Farm Assessment of Tillage Impact on Soil Carbon and Associated Soil Quality Parameters.” Environmental Research Letters 2: 045023. P. P. afforestation/ reforestation. Policy Brief November 2009. Friedlingstein. 4: Agriculture.jp. Climate Change 2007: Synthesis Report—Summary for Policymakers.fao. and Fernandes.’’ Soil Science Society of America Journal 57. livestock.v-c-s. Gibbs. Emphasis is placed on cost-effective approaches that do not add excessively to the burden of project management.4 CARBON ASSESSMENT IN THE WORLD BANK’S SUSTAINABLE LAND MANAGEMENT PORTFOLIO Carbon Assessment Using the Ex Ante Appraisal Carbon-Balance Tool The World Bank is increasingly looking to assess the carbon footprint of its operational work across sectors. S. rice cultivation. 2009. Sustainable Agricultural Land Management Methodology IPCC. Niles. and water development projects on GHG emissions and carbon sequestration. “How Positive is the Feedback Between Climate Change and the Global Carbon Cycle?” Tellus 55B: 692–700. Global Carbon Project. farmers in developing countries (http://www. and Thomson..” Ann. IPCC. Land Use. 192–194.. IPCC. D. when available. “Temperature-Associated Increases in the Global Soil Respiration Record. “Managing Carbon Sequestration in Soils: Concepts and Terminology. and Lal. London.B. referred to as Sustainable Agricultural Land Management (SALM). Ecosystems and Environment 87: 111–117. J. H. H. P. B. Carbon assessment in EX-ACT is implemented in the following three steps: ƒ General description of the project (geographic area. K. “Breeding Crop Plants With Deep Roots: Their Role in Sustainable Carbon. org/tc/exact/en/) has been developed with this objective in mind. and Foley. The Ex-Ante Appraisal Carbon-Balance Tool (EX-ACT. It also has resources (linked tables and maps) that can assist in gathering the information necessary to run the model. A.org/files/VM0017%20SALM%20Methodolgy%20 v1. and energy) ƒ Computation of carbon balance with or without the project using IPCC default values and. and Water Sequestration. 2011. Dufresne. 10. M. 108 (3): 407–418. A detailed analysis of lessons learned in testing EX-ACT in World Bank agriculture projects can be found in World Bank (2012). organic soils.” Soil Tillage Research. 2007. 1–3... EC O N O M I C A N D S E CT OR WORK 17 . J. thereby indicating the overall effects on the carbon balance. Bot. Nutrient. J.C H A P T E R 2 — S O I L ORGANIC CARBON DYNAMICS A ND A SS ES S MENT METH OD S 2. it can easily be up-scaled at the program/sector level. Eswaran. E. Bond-Lamberty. 2006. and Forestry. iges. I. It is easy to use in the context of program formulation.ipcc-nggip.” Nature 464: 579–582. ``Organic Carbon in Soils of the World. annual/perennial crops.” Agriculture. 1993. and Cox.

” Boreal Environmental Research 13: 120–130. “Carbon Emission From Farm Operations. Department of Agriculture.. 2001.C. M. K. Post. and Forestry.0 Lal.usda. “Global Patterns of Carbon Dioxide Emissions From Soils. R. and Bliss..” In Proceedings of the Symposium on Carbon Sequestration in Soils Science.J. and M. U..” Environment International 30: 981–990. Springer-Verlag. Ravindranath. Carbon Foot-Printing of ARD Projects: Testing the Ex-Ante Carbon Balance Appraisal Tool. Hakkinen. L. ed. K. Muukkonen. C.jpg. and E.” Global Biogeochemical Cycles 9: 23–36. 2000. “Monitoring and Verification of Soil Organic Carbon Sequestration.” Environment International 29: 437–450. “Global Soil Regions. “The Costs of Monitoring Changes in Forest Soil Carbon Stocks. Raich. and Bliss. Carbon Mitigation and Roundwood Production Projects. Natural Resources Conservation Service. M. Cambridge University Press. Monitoring and Beyond. “Monitoring and Verifying Changes of Organic Carbon in Soil. World Bank. H. Makipaa. R.. Berlin. Malone. Izaurralde.. Rosenberg. Ostwald. Land Use. 2008. P. J. N.18 CHAPTER 2 — S OIL OR GA NIC CA R B ON D YNA MIC S A ND A SS ES S MENT M ETH OD S Lal. W. Izaurralde.. et al. DC. M. R. Mann. R. 1995. N. 2012. Intergovernmental Panel on Climate Change. Watson. C. L. Robert et al. Columbus. Advances in Global Change Research.” Climatic Change 51 (1): 73–99. 2008..gov/use/worldsoils/mapindex/orders.. CARBON SEQUESTRATION IN AGRICULTURAL SOILS . Izaurralde. OH: Batelle Press.... ed. 2003. Washington. World Bank. Mann. N. R.L. Land-Use Change. Carbon Inventory Methods Handbook for Greenhouse Gas Inventory. W. C. 2004. R. 1999. Post.S.” http://soils. Cambridge. “Soil Erosion and the Global Carbon Budget.. and Potter. N.

and livestock and manure management. but this has to be put in the perspective of emissions associated with the process of irrigation Use of cover crops/green manure increases the biomass returned to the soil and thus increases soil carbon stock Introduction of earthworms to improve aeration and aid organic matter decomposition in the soil profile Use of improved crop varieties—Improved crop varieties help to sequester carbon in the soil through increased above. and woodlots into croplands helps to store more carbon. This chapter documents the evidence from the published literature on the impacts of agricultural land management practices and agricultural land-use changes on soil carbon sequestration in Africa.ANALYSE S OF SOIL CARBON SEQUES TR ATION Chapter 3: 3. Mitigation of GHG in agriculture can involve several practices such as avoiding the conversion of native forests and grasslands to croplands. abandoned. and mitigating GHG emissions (table 3. crop residues also prevent loss of carbon from the soil system Afforestation—Establishment of new forests on nonforest land (cropland.1 META-ANALYSES OF SOIL CARBON SEQUESTRATION INTRODUCTION A range of practices has been suggested as important to soil carbon sequestration and thus of potential relevance to increasing crop yield. less environmentally friendly due to nitrous oxide (N2O) emissions associated with N fertilizers. and emissions associated with transport of fertilizers Water management to increase productivity.and below-ground biomass production and soil organic carbon accumulation Mulching/residue management—Improves soil moisture. or degraded lands) increases carbon stock through the increase in above-ground biomass as well as greater organic materials input for soil decomposition Application of inorganic fertilizers and manure to stimulate biomass production—Chemical fertilizers are.19 C H A P T E R 3 — M E TA. Grassland.1). less environmentally friendly due to nitrous oxide (N2O) emissions associated with N fertilizers. EC O N O M I C A N D S E CT OR WORK . The impacts of changes in agricultural practices on soil carbon stocks such as changes to crop rotation or reduced grazing are usually more subtle than those brought about by more dramatic changes in land use such as conversion of cropland to forest or grassland to tree crops. or seriously degraded agricultural lands. however. however. The main emphasis is on obtaining better estimates of soil carbon sequestration TABLE 3. prevents soil erosion. and Latin America. depletion of soil organic carbon.1: Practices That Sequester Carbon in Forest. and increases soil organic matter when incorporated into the soil. the greenhouse cost of fertilizer production. Asia. the greenhouse cost of fertilizer production. orchards. optimize water use. restoration of barren. increasing the resilience of agroecosystems. enhancing removal of carbon from the atmosphere through a range of soil and water management practices including crop diversification. grassland. and emissions associated with transport of fertilizers Application of inorganic fertilizers and manure to stimulate biomass production—Chemical fertilizers are. and Cropland FOREST GRASSLAND CROPLAND Protection of existing forests—Avoided deforestation preserves existing soil C stocks and prevents emissions associated with biomass burning and soil exposure by land clearing Improved grassland management—Optimize stocking rates to reduce land degradation. diversify production. and increase income Introduction of improved crop varieties Application of biochar and other soil amendments Source: This study. and methane emissions through enteric fermentation No or reduced tillage—Reduces the accelerated decomposition of organic matter associated with intensive (conventional or traditional) tillage Reforestation—Increasing tree density in degraded forests increases carbon accumulation Introduction of improved pasture species and legumes to increase above.and below-ground biomass production Establishment of pasture on degraded land reintroduces large amounts of organic matter into the soil Agroforestry/tree-crop farming—Introduction of fruit trees.

20

CH A PTER 3 — META -A NA LY S ES OF SOIL CA R B ON SEQU ES TR ATION

rates. This is one important element in making comprehensive assessments of the impact of soil quality on agricultural
sustainability and greenhouse mitigation potentials.

3.2

METHODS

Analysis
Most studies reported concentrations of carbon in soil
samples (Cc in g kg−1). These were converted to volumes and
then areas to calculate stocks (Cs in kg−1 ha−1) and sequestration rates (kg ha−1 yr−1) using bulk density (BD, in g cm−3) and
sample soil depth (D, in cm):

Searches and Data Sources
Searches were carried out using online database and
search tools, including ProQuest, Scopus, Sciencedirect,
SpringerLink, Wiley Science Library, and Google Scholar with
an emphasis on key terms such as soil organic matter, organic matter, soil organic carbon, soil carbon, carbon sequestration, soil sequestration, and soil properties, in combination
with geographical descriptors (e.g., countries and continents)
and terms for particular agricultural practices.
Inclusion-Exclusion Criteria
For soil fertility and surface management effects that are
commonly studied in agricultural science, only studies of at
least 3 years duration were included. A major effort was made
to collect data from as many long-term studies as possible.
Almost all studies adopted formal experimental designs,
setting up control and treatments. The variations applied in
the treatments accounted for the different levels of carbon
added to the soil. In a few cases where paired designs were
employed, logical contrasts were made with appropriate controls using final values of stocks under each treatment.
Experimental study designs are rare for land-use change
effects. Most adopted nonexperimental designs such as
chronosequence where adjacent plots of different ages were
compared, paired studies where adjacent plots of different
land uses and similar ages were compared, or repeated samples where same plot was measured over time. Only studies
of at least 4 years duration were included, and where repeated measures were made, sequestration rates for the longest
time interval were taken. A major reason for excluding papers
with data on different land uses was difficulty in assuming
particular sites could be taken as a reasonable control.
Effect Sizes
The effect of a land management practice was estimated by
comparing the final level of soil carbon stock in one treatment
with that practice and an appropriate control. Thus, all soil
carbon sequestration rates are estimates of effect size—the
difference with respect to a control—and thus represent the
marginal benefit of adopting that practice. Effect sizes were
estimated for all logical contrasts with sufficient information
provided in a paper.

Cs = BD x Cc x D x 10,000
In a few studies, value was given in terms of percent soil
organic matter. In these cases, concentrations of Cc (g kg−1)
were calculated as
Cc = 0.58 x OM% x 10
In some cases, only a single value, either initial or average
across treatments, was provided for bulk density. In these
cases, that value was assumed to apply to all treatments. If
no bulk density information was provided in a paper (or other
reports about the same study cited by that paper), then bulk
density was estimated using known pedotransfer functions
(that is, simple regression equations) developed for that region
or extracted from the International Soil Reference Information
Center–derived soil properties database (www.isric.org).
Effect sizes and importance of contextual variables (e.g.,
temperature, precipitation, duration, and soil type) were
summarized by means and 95 percent confidence intervals
for the mean. Associations of the context variables with carbon sequestration were assessed by grouping observations
into a few classes so that nonlinear patterns could be clearly
identified. Geographical distribution of datasets is shown in
figure 3.1, while the characteristics of the estimates with
respect to duration of study, soil sampling depth, and experimental design are shown in Appendix 3.1.

3.3

RESULTS

Contextual Factors and Soil Carbon Sequestration
Climate
Climate significantly influences large-scale patterns of soil
carbon sequestration. In this study, higher sequestration
rates were observed in the wettest locations (figure 3.2).
There was also a trend to lower sequestration rates in the
coolest and warmest conditions (figure 3.3). Sites in warmer
and middle temperature regions tended to accumulate soil
carbon more rapidly than those in colder regions, whereas
semi-humid areas had higher average rates than their semiarid counterparts. Potter et al. (2007) explored interactions
with residue management practices in maize fields at six

CARBON SEQUESTRATION IN AGRICULTURAL SOILS

21

C H A P T E R 3 — M E TA- ANALYSE S OF SOIL CARBON SEQUES TR ATION

FIGURE 3.1: Geographical Distribution of Carbon Sequestration Estimates

Carbon sequestration
number of estimates
1–10
11–30
31–50
51–100
101–200
201–630

Source: This study.

sites across a wide range of annual temperature regimes in
Mexico and discovered that as temperature increased, more
crop residues needed to be retained to increase levels of soil
organic carbon. An increase in soil temperature exacerbated
the rate of mineralization, leading to a decrease in the soil
organic carbon pool (SOC). However, decomposition byproducts at higher temperatures may be more recalcitrant
than those at lower temperatures.

soil profiles give some indication of humus, clay minerals, or
metal oxides accumulating in their layers. In Asia, the highest
sequestration rates and variability were observed on oxisols,
formed principally in humid tropical zones under rain forest,
scrub, or savanna vegetation on flat to gently sloping uplands. Oxisols are typically found on old landscapes that have
been subject to shifting cultivation for several years.
Duration

Soils
Soil type, especially those with a higher clay content, leads to
higher carbon sequestration rates. However, obtaining comparable data is difficult as not all studies provide sufficient
information on soil properties, and those that do use different soil classification schemes at different levels of detail. As
a first-level analysis, the reported soil types were reclassified
into major soil orders of the U.S. Department of Agriculture
classification system (figure 3.4). Carbon sequestration rates
were highest and also highly variable on inceptisols in Africa
and Latin America. Inceptisols are relatively young soils
characterized by having only the weakest appearance of horizons, or layers, produced by soil-forming factors. Inceptisol

EC O N O M I C A N D S E CT OR WORK

Longer term studies on average have resulted in lower
sequestration rates, as would be expected from saturation
(figure 3.5). Most of the potential soil carbon sequestration
takes place within the first 20 to 30 years. The pattern of
change in sequestration rates is nonlinear and differs between major groups of practices, with the highest rates at
intermediate times and low or even negative rates in the
short term.
Nutrient Management
Fertilizer use sequesters carbon by stimulating biomass production. Judicious fertilizer application also counters nutrient
depletion, reduces deforestation and expansion of cultivation

22

CH A PTER 3 — META -A NA LY S ES OF SOIL CA R B ON SEQU ES TR ATION

FIGURE 3.2: Soil Carbon Sequestration and
Precipitation

FIGURE 3.3: Soil Carbon Sequestration and
Temperature

Africa

Africa
3,000
carbon sequestration (kg C/ha/yr)

carbon sequestration (kg C/ha/yr)

3,000
2,500
2,000
1,500
1,000
500

2,500
2,000

1,500
1,000

500

0

0
<500

500–1,000

1,001–1,500

<20

<1,500

annual precipitation (mm)

carbon sequestration (kg C/ha/yr)

carbon sequestration (kg C/ha/yr)

>30

Asia

Asia

1,250

1,000

750

500

250

800

600

400

200
<500

500–1,000 1,001–1,500
annual precipitation (mm)

< 10

1,500+

10 – 20

20 – 30

30+

mean annual tempeature (°C)
Latin America

Latin America
800

1,200
carbon sequestration (kg C/ha/yr)

carbon sequestration (kg C/ha/yr)

20–25
25–30
mean annual temperature (°C)

600

400

200

1,000
800
600
400
200
0
–200

<500

Source: This study.

500–1,000 1,000–1,500
annual precipitation (mm)

1,500+

<15

15.20

20.25

25+

mean annual temperature (°C)
Source: This study.

CARBON SEQUESTRATION IN AGRICULTURAL SOILS

6). Phosphorus and Potassium compound fertilizers N = Nitrogen. in some cases.000 Across the full dataset. Latin America Vertisols Ultisols Oxisols soil type to marginal areas. 2011).000 carbon sequestration (kg C/ha/yr) Vertisols Ultisols Oxisols soil type ƒ Using nitrification inhibitors that hold-up microbial processes leading to nitrous oxide formation The average effect size of applying fertilizer was an additional 124 kg C ha−1 yr−1 sequestered for Latin America.000 –1. Strategies to promote nutrient use efficiency include the following: Mollisols Inceptisols Entisols Andisols Alfisols –2. Another meta-analysis at the global level concluded that addition of nitrogen fertilizer resulted.000 carbon sequestration (kg C/ha/yr) Source: This study.000 carbon sequestration (kg C/ha/yr) 4.000 4.C H A P T E R 3 — M E TA. the combination of fertilizer with locally available manure sources. Alvarez’s (2005a) analysis of a global dataset indicated that for every additional tonne of nitrogen fertilizer applied. in a 3.000 2.Nitrogen.000 2. and 264 kg C ha−1 yr−1 for Africa (table 3. The majority of studies have designs focused on the influence of different levels of nitrogen and. K = Potassium were significantly higher than other combinations (Figure 3.7). on average.ANALYSE S OF SOIL CARBON SEQUES TR ATION FIGURE 3. P.000 3.000 4.000 3. some studies show that integrated management of N. EC O N O M I C A N D S E CT OR WORK Biofertilizers are an essential component of organic farming.000 3.5 percent increase in soil carbon in agricultural ecosystems (Lu et al. P = Phosphorus. Soil organic carbon levels clearly increased under nitrogen fertilization only when crop residues were returned to the soil.000 0 1. two more tonnes of soil organic carbon were stored in fertilized than unfertilized plots.000 2. Within individual experiments.2). They contain living microorganisms that colonize the rhizosphere and promote plant growth by increasing the supply of nutrients through nitrogen fixation or enhancing the availability of primary nutrients to the host plant by solubilizing phosphorus and other nutrients. and K fertilizers is important to maintaining or increasing soil carbon and nitrogen and thus soil fertility. 222 kg C ha−1 yr−1 for Asia. Asia Mollisols Inceptisols Entisols Aridisols Andisols Alfisols 0 1. and increases crop yields. studied average sequestration rates with NPK . Aggregating across locations and cropping systems there was no significant association between level of N applied across annual cropping cycles and carbon sequestration rates (figure 3.4: Soil Carbon Sequestration and Soil Order Africa ƒ Adjusting application rates based on assessment of crop needs Vertisols Ultisols ƒ Minimizing losses by synchronizing the application of nutrients with plant uptake soil type Oxisols ƒ Correcting placement to make the nutrients more accessible to crop roots (microfertilization and microdosing) Mollisols Inceptisols ƒ Using controlled-release forms of fertilizer that delay its availability for plant uptake and use after application Andisols Alfisols 0 1. The microorganisms in 23 .

5: Soil Carbon Sequestration and Time Africa carbon sequestration (kg C/ha/yr) 4.000 1.500 2.000 carbon sequestration (kg C/ha/yr) 1.500 3.600 4.500 3.000 2.500 1.24 CH A PTER 3 — META -A NA LY S ES OF SOIL CA R B ON SEQU ES TR ATION FIGURE 3.000 1.500 1.500 2.200 1.000 carbon sequestration (kg C/ha/yr) carbon sequestration (kg C/ha/yr) 5–10 duration of study (years) >30 3.000 All 3.000 2.000 1.000 Nutrient manangement 2.250 600 1.000 500 Land-use change 4.000 400 750 200 500 250 0 <5 5–10 10–20 20–30 duration of study (years) 30+ <5 5–10 10–20 20–30 duration of study (years) 30+ CARBON SEQUESTRATION IN AGRICULTURAL SOILS .400 1.500 1.500 500 Tillage and residue management 1.000 500 0 0 <5 5–10 duration of study (years) <5 11–20 5–10 11–20 20–30 >30 duration of study (years) Asia Tillage and residue management All carbon sequestration (kg C/ha/yr) 1.000 800 600 400 200 0 <5 0 5–10 11–20 duration of study (years) <5 11–20 4.500 2.500 3.

000 Nutrient management 2.000 –250 –1.200 800 600 400 200 Tillage and residue management 1.000 500 0 –500 –1.000 1.500 0 <5 5–10 10–20 20–30 duration of study (years) Source: This study.25 C H A P T E R 3 — M E TA.000 600 1.500 Nutrient management 750 5–10 10–20 20–30 duration of study (Years) 1.000 0 500 0 –500 <5 10–20 5–10 20–30 <5 30+ duration of study (Years) carbon sequestration (kg C/ha/yr) carbon sequestration (kg C/ha/yr) 500 250 0 30+ Land-use change 1.ANALYSE S OF SOIL CARBON SEQUES TR ATION 95% CI carbon sequestration (kg C/ha/yr) 1.000 200 500 0 0 <5 5–10 10–20 20–30 duration of study (years) Land-use change <5 30+ 5–10 10–20 20–30 duration of study (years) 30+ Latin America All 1. EC O N O M I C A N D S E CT OR WORK 30+ <5 5–10 10–20 20–30 duration of study (years) 30+ .500 400 1.500 carbon sequestration (kg C/ha/yr) carbon sequestration (kg C/ha/yr) 1.500 800 2.

Note: N = Nitrogen.7: Soil Carbon Sequestration and Fertilizer Combinations (Means and 95 Percent Confidence Intervals. FIGURE 3. NK = Nitrogen and Potassium only. NPK = combination of Nitrogen. NP = Nitrogen and Phosphorus only. Note: N = Nitrogen only. PK = Phosphorus and Potassium only. n = 285) 500 carbon sequestration (kg C/ha/yr) 400 300 200 100 0 N NP PK NK NPK fertilizer mix Source: This study. CARBON SEQUESTRATION IN AGRICULTURAL SOILS . Phosphorus and Potassium.6: Soil Carbon Sequestration and Application Levels of Nitrogen Fertilizer (Means and 95 Percent Confidence Intervals.26 CH A PTER 3 — META -A NA LY S ES OF SOIL CA R B ON SEQU ES TR ATION FIGURE 3. n = 285) carbon sequestration (kg C/ha/yr) 600 400 200 0 <100 100–200 200–300 300+ N fertilizer (kg N/ha/yr) Source: This study.

8 times greater for compost than for manure.4 t C ha−1 yr−1. The impact of composting on emissions post-land application is of further interest. and financial income (Sumberg 2003).3). Net CH4 flux was minimal (less than 0. manure. biofertilizers restore the soil’s natural nutrient cycle and help in building soil organic matter. Three studies reviewed indicate that biofertilizers sequestered about 1. manure. which were 1. moisture content. Pattey. Trzcinski.27 C H A P T E R 3 — M E TA. animal power. 2007) and Thailand (Matsumoto. or ownership domains.459 −42 2. In China. Paisancharoen.01 t CO2e ha−1 yr−1). Manure sequestered more carbon than fertilizer. suggesting that the organic matter stabilization during composting reduces post-application respiration losses. Thelen. Yields EC O N O M I C A N D S E CT OR WORK also increased with manure application and accumulation of soil carbon but with patterns that depend on crop.7 t CO2e ha−1 yr−1). Fronning.ANALYSE S OF SOIL CARBON SEQUES TR ATION TABLE 3. and Desjardins (2005) found that compared to untreated manure storage.2). economic movement of crop residues. One major constraint is the availability of manure and labor costs associated with collecting and processing it. and animal power (table 3. Crop-livestock integration can occur in space. However. yielding 61 kg C ha−1 yr−1 more in Africa. and aeration status. the gains happened in the first few years and were not followed by further yield improvements (Zhang et al. while in rice-based systems. Manure application to agricultural soils can reduce nitrous oxide emissions by displacing N fertilizer use. Biofertilizers are more environmentally friendly and cost-effective relative to chemical fertilizers. The agronomic and economic justification for the integration is based on the exchange of four main types of resources: crop residues. management. and livestock is markedly curtailed.2: Nutrient Management and Soil Carbon Sequestration Rates (kg C ha−1 yr−1) PRACTICE MEAN LOWER 95 PERCENT CONFIDENCE INTERVAL OF MEAN UPPER 95 PERCENT CONFIDENCE INTERVAL OF MEAN NUMBER OF ESTIMATES Africa Chemical fertilizer 264 169 359 30 Manure 325 224 427 30 Chemical fertilizer 222 157 288 297 Manure 465 374 556 146 1. Close spatial integration is required for crop-livestock interactions involving crop residues. and 331 kg C ha−1 yr−1 more in Latin America (table 3. these land emission impacts were small when compared to soil C sequestration rates. time. while untreated manure application generated higher N2O emissions than did compost (0. yields of maize and maize-wheat systems increased over the longer term. and Hakamata 2008) have pointed to trends of declining livestock numbers and speculated on impacts of this on manure application practices. 2009). Temporal integration can only occur after some form of spatial integration has taken place. hindering interaction. At large distances (scale). These benefits have already been recognized in efforts to divert organic waste from landfills. depending on carbon-to-nitrogen ratio. Studies in Nepal (Acharya et al. Methane emissions can also be minimized by displacing anaerobic storage options with aerobic decomposition. The spatial domain integration is based on the idea that crops and livestock activities can be colocated with the level of integration increasing as the scale becomes smaller. Integration in the temporal domain connotes that crop and livestock production can take place simultaneously (in parallel) or can be temporally segregated (in sequence).960 3 Chemical fertilizer 124 −15 262 74 Manure 455 23 887 25 Asia Biofertilizer Latin America Source: This study.9 versus 0. and Min (2008) examined GHG fluxes following land application of solid beef manure and composted dairy manure over a 3-year period. manure. The impact of manure on soil carbon sequestration is best realized in farming systems that integrate crops and livestock. and the latter is important given the . 243 C ha−1 yr−1 more in Asia. composting reduced total GHG emissions (CH4 and N2O) by 31 to 78 percent.

One of the main barriers to the use of crop residues and mulch for soil fertility management is the numerous competing uses for feed. the agricultural preparation of the soil for planting. and biofuel. while low-quality residues tend to immobilize nitrogen. In general. Examples include intercropping maize and pigeon pea. while others looked at the effects of grazing crop residues on soil carbon sequestration. fodder. However. The quantity of residue produced is a function of the cropland area and agronomic practices. crop residue. integration in the management domain is not a prerequisite for successful beneficial crop-livestock interaction (Sumberg 2003).28 CH A PTER 3 — META -A NA LY S ES OF SOIL CA R B ON SEQU ES TR ATION TABLE 3. The effects of crop residues and mulches on carbon sequestration are highest in Latin America and lowest in Africa (table 3. Crop-livestock integration can minimize the trade-off in the use of residues for feed (see the section of this report on nutrient management on page 21). thereby promoting control and secure access to resources. the formal and informal links between crop and livestock producers for accessing manure. In Latin America. and bioethanol production in Mozambique. including tillage method. thatch.4). thereby allowing water to gently percolate into the soil. ** = some importance. but it requires more labor. seasonality of feed and water for livestock. Others were on the effects of sugar cane residues on sequestration. use of straw from rice and other crop residues was found to be prevalent in Asia. Crop Residue Management and Tillage Crop residues are an important renewable resource for agroecosystems. As large carbon losses occur under very wet conditions. has three primary purposes: to facilitate seed germination CARBON SEQUESTRATION IN AGRICULTURAL SOILS . or power implies that though desired. ƒ increasing aggregation of soil particles. Apart from biomass from trees. ƒ intercepting raindrops. Controlled grazing and the establishment of plots of permanent forages for direct grazing can also reduce conflicts between soil organic matter accumulation and grazing needs.3: Relative Importance of the Four Domains of Integration on Crop-Livestock Interaction SPACE TIME Crop residue *** ** * ** Manure *** * * ** Animal power *** *** * * * ** *** * Financial income OWNERSHIP MANAGEMENT Source: Adapted from Sumberg (2003).8). *** = much importance. most studies looked specifically at the effects on soil carbon sequestration of mulching or incorporating residues relative to burning. High-quality residues of perennial legumes are generally the most effective in supplying nitrogen in the short to medium term. integration in the ownership domain is not required for beneficial croplivestock interaction. Tillage. and GHG emissions by ƒ aiding nutrient cycling. Cereals are two to three times better than legumes at sequestering carbon. Note: * = little importance. Crop residue management influences soil resilience. Last. desirable results will be achieved if integrated foodfeed-energy systems are tailored to specific local conditions. While ownership may increase the efficiency of the beneficial effects of interaction. the best results are obtained when residues are applied shortly before the beginning of the rainy season. Cereals also have higher concentrations of lignin that are resistant to decomposition. ƒ lowering soil evaporation. The quality and quantity of residues markedly influence the amount of carbon sequestered (figure 3. income generation. Integration in the ownership domain underscores the fact that a given croplivestock combination can be owned by the same or a different entity. agronomic productivity. Zero grazing involving the confinement of livestock in a stall and developing a cut-and-carry fodder system can make for more residue retention on the field. integration in the management domain implies that management of crop and livestock production may or may not be in the hands of the same entity and that management may not necessarily coincide with ownership of both crops and livestock. The establishment of bioenergy plants to meet the demand for biofuel may also help. and ƒ reducing run-off and erosion. and using cookstoves for rural dwellers in Malawi and using agroforestry systems for food.

4: Tillage.1: Crop Residue Management in Irrigated Fields in Indonesia Source: Curt Carnemark/World Bank.ANALYSE S OF SOIL CARBON SEQUES TR ATION PHOTO 3. and Soil Carbon Sequestration Rates (kg C ha−1 yr−1) PRACTICE MEAN LOWER 95 PERCENT CONFIDENCE INTERVAL OF MEAN UPPER 95 PERCENT CONFIDENCE INTERVAL OF MEAN NUMBER OF ESTIMATES Africa Crop residues 374 292 457 46 Mulches 377 159 595 6 Cover crops 406 298 515 24 No-tillage 370 322 418 108 Crop residues 450 379 521 189 Mulches 565 371 759 53 Cover crops 414 233 594 38 No-tillage 224 97 351 48 Crop residues 948 638 1. Crop Residue Management.258 56 Mulches 748 262 1. EC O N O M I C A N D S E CT OR WORK . TABLE 3.29 C H A P T E R 3 — M E TA.108 16 Cover crops 314 108 520 33 No-tillage 535 431 639 249 Asia Latin America Source: This study.

and they are the precursor to conservation agriculture.000 ha under conservation agriculture. While plowing loosens and aerates the topsoil and facilitates seedling establishment. Recent experience in Zambia—conservation agriculture with trees—suggests that the system holds promise for replenishing soil fertility and improving productivity and rural livelihoods. and reduction in soil organic matter. Depending on the amount of residue left on the soil surface.2). water. by creating a smooth. and to control weeds. CARBON SEQUESTRATION IN AGRICULTURAL SOILS . decrease in infiltration rate. increase in soil erosion and loss of nutrients.4). Canada. Conservation agriculture is based on ƒ minimum soil disturbance through mechanical tillage. plow.8: Mean Soil Carbon Sequestration and Levels of Residue Returned 1. manures and crop residues into the soil. more appropriately referred to as intensive tillage.9). In this study. and (3) rotation of grains with legumes in the field. Most of the conservation tillage systems are large-scale farms in the United States. and harrow for seedbed preparation. Argentina. Conventional tillage leaves the least residue on the soil surface. ƒ permanent soil cover through residue management. Brazil. (2) retention of crop residue from previous harvests in the field or use of other mulches from the tree component (Faidherbia albida) or other cover crops.000 carbon sequestration (kg C/ha/yr) 800 600 400 200 0 <3 3–5 5–8 8+ residue application (t/ha/yr) Source: This study. 2011). to incorporate fertilizer. entails motorized multiple farm operations with mold board. uniform soil surface for planting. disk. and Australia. the holistic agricultural production system that integrates management of soil. destruction of soil aggregates. Conservation tillage systems leave the most crop residues on the surface. and biological resources (Liniger et al. Conservation agriculture in Zambia entails (1) dry season land preparation using minimum tillage methods and utilizing fixed planting stations (small shallow basins). and conservation tillage (figure 3. tillage systems can be broadly classified into conventional. the 95 percent confidence intervals are shown as whiskers. and ƒ crop rotation and diversification using legumes and green manure or cover crops (figure 3. Notes: n = 165. The conventional method. carbon sequestration under conservation tillage ranged from 224 kg ha−1 yr−1 for Asia to 535 kg ha−1 yr−1 for Latin America (table 3. Africa lags behind with only about 500. Conventional tillage should not be confused with traditional tillage techniques involving manual or animal-drawn operations. it can lead to many unfavorable effects including soil compaction. reduced.30 CH A PTER 3 — META -A NA LY S ES OF SOIL CA R B ON SEQU ES TR ATION FIGURE 3. increase in evaporation loss.

The ridges are formed from crop residues that are left on the soil. and field cultivators. less tillage reduces labor costs. Cover crops can also improve soil quality by increasing soil organic carbon through their biomass. Cover crops help to improve soil macronutrients and micronutrients and are termed green manure because of their ability to enhance soil fertility. Soil is disturbed prior to planting and crop residues are incorporated using chisels. EC O N O M I C A N D S E CT OR WORK Cover Crops In this study.31 C H A P T E R 3 — M E TA. Higher soil moisture also helps to increase cropping intensity rather than leave the field fallow. Ridge tillage Ridge tillage is similar to the traditional systems with planting on preformed ridges. Only the soil area containing seed rows are tilled. nutrients. aims for 100% soil cover and does not involve soil disturbance through tillage. reduce erosion. farmers adopting the system have been better able to plant close to the onset of the rains. Reduced tillage Conservation tillage Greater than 30% crop residue on the soil (>1.000 farmers used this system at the end of 2010. cover crops can be used to control weeds and supply nutrients. conserves soil moisture and helps increase soil organic matter. while the top of the ridges are leveled off at planting. It also includes planting operations such as hoe drills and air seeders. the practice of growing cover crops in situ was distinguished from mulches and crop residues of main harvested crops. The soils are tilled at specific intervals e. and this figure was projected to rise to 250. sweeps.g.000 kg ha-1 crop residue equivalent) 15% to 30% residue cover on the soil (500 to 1. The tree component provides mulch and nutrients. Soil erosion on strip tilled farms is much lower than for conventional tillage. Residue management is used in conjunction with crop rotation. and crop yields. or every other year depending on cropping sequence. Strip tillage requires higher precision planters compared to no tillage system. groundnut and mucuna. Also. fertilizer should be applied in slightly higher quantities. hills or bunds that provides warmer conditions for plant growth. Source: This study. improve water use efficiency and reduce energy use.000 farmers by 2011. at the introduction of a crop in the rotation sequence. As an option to increased herbicide use. Strip tillage allows for a better seedbed and for nutrients to be better adapted to the plant’s needs. The rows are maintained in the same location each season.9: Classification of Tillage Systems Based on Crop Residue Management Tillage Systems Conventional tillage Less than 15% residue cover on the soil (< 500 kg ha-1 crop residue equivalent) No tillage Also called zero tillage. Helps to increase soil moisture. By eliminating the need for laborious land preparation. and they also help in .ANALYSE S OF SOIL CARBON SEQUES TR ATION FIGURE 3. To avoid yield depression during transition period (3 to 5 years). Green manure crops are commonly leguminous crops with high nitrogen content. or rotation from annual to perennials. Examples include cowpea. and adjustment of planting density. a rotational system may include both mulch tillage and no tillage. The system is mainly used on poorly drained soils. For instance. organic matter. representing some 30 percent of the population of small-scale farmers in Zambia. The primary purpose of mulch tillage is to increase soil organic matter and tilth. cover crops. Using conservation agriculture. appropriate cover crop mix for weed suppression is essential. the residue cover prevents soil erosion. yields have doubled for maize and increased by 60 percent for cotton compared to conventional tillage system. Rotational tillage This is a system in which different tillage methods are used to establish different crops during a crop rotation sequence. Over 180.000 kg ha-1 crop residue equivalent) Strip tillage Mulch tillage It uses minimum tillage by combining the soil aeration benefits of conventional tillage with the soilprotecting advantages of no tillage. Like other conservation tillage systems.

Crop Rotation Crop rotation is a key complementary practice for successful implementation of no-tillage. CARBON SEQUESTRATION IN AGRICULTURAL SOILS . protecting the soil from surface runoff and suppressing weeds. and ƒ diversifying the rotation to include nitrogen-fixing legumes. but variation is high (figure 3. The succeeding crop may be of a different species (e. Agroforestry maintains soil organic matter and biological activity at levels suitable for soil fertility. and the planned rotation may be for 2 or more years. harvesting water. TABLE 3.g. yams. while terracing sequestered the least (table 3. the sequence is usually maize/barley. thereby There is a tendency toward higher sequestration rates in triple cropping systems. cassava. while in Ethiopia. managing excess water. reduced soil erosion.. groundnuts. Rotation diversification is different in Africa compared to Latin America. Intensifying rotation means replacing a fallow with another crop. increased soil water management. the traditional element of crop rotation is the replenishment of nitrogen through the use of legumes in sequence with other crops.32 CH A PTER 3 — META -A NA LY S ES OF SOIL CA R B ON SEQU ES TR ATION The apparent lower level for double compared to single or triple cropping may reflect differences in soils. sesame. and reduced pest and diseases. ƒ including perennial crops in the rotation. ƒ producing large amounts of biomass and residue for soil protection and incorporation in the soil.5: Crop Rotation and Soil Sequestration Rates (kg C ha−1 yr−1) MEAN LOWER 95 PERCENT CONFIDENCE INTERVAL OF MEAN UPPER 95 PERCENT CONFIDENCE INTERVAL OF MEAN NUMBER OF ESTIMATES Diversify rotation 378 306 451 49 Intensify rotation 342 277 407 55 345 87 604 43 PRACTICE Africa Asia Intensify rotation Latin America Intensify rotation 331 165 496 25 Diversify rotation 136 −62 334 43 Source: This study. Two variants of crop rotation observed in the review are rotation intensification and diversification (table 3. millet.6). ƒ maintaining a continuous sequence of living vegetation. Agroforestry Agroforestry is an integrated land-use system combining trees and shrubs with crops and livestock. followed by maize. In the Sahel. cowpea. climate. and tree legumes.5). Rainwater harvesting is particularly important for rain-fed agriculture in arid and semiarid regions. a typical cropping sequence is millet/sorghum. Crop rotation is the deliberate order of specific crops sown on the same field. Conveyance and distribution efficiency are also important measures in irrigation. Terracing on steep slopes and cross-slope barriers helps in reducing surface runoff. In Africa. and maximizing water storage. Improved irrigation sequestered carbon the most. and cropping systems rather than effects of cropping intensity. while diversifying rotation implies altering cropping sequences within or across years while keeping the same number of crops in the rotation. followed by sorghum.10). improving soil aggregate stability. grain crops followed by legumes) or variety from the previous crop. Rotating to a different crop such as cowpea or soybean usually results in higher grain yields when compared to continuous cropping of maize. It also contributes to agro-ecosystem resilience by controlling runoff and soil erosion. Other benefits of crop rotation include improved soil fertility. and tef. The practice aims at minimizing the effects of seasonal variations in water availability due to droughts and dry periods and enhancing the reliability of agricultural production. The recommended crop rotation strategies include Water Management Improved water productivity in agriculture is achieved by reducing water loss.

EC O N O M I C A N D S E CT OR WORK Triple of more .250 1. FIGURE 3.33 C H A P T E R 3 — M E TA.ANALYSE S OF SOIL CARBON SEQUES TR ATION PHOTO 3.500 1.000 750 500 250 Single Double cropping intensity Source: This study. Note: The 95 percent confidence intervals are shown as whiskers (n = 536).2: Water Management in a Field in India Source: Ray Witlin/World Bank.10: Mean Soil Carbon Sequestration and Cropping Intensity carbon sequestration (kg C/ha/yr) 1.

and occurs in different ecosystems ranging from dry lands to wet tropical climates. Farmers have frequently reported significant crop yield increases for maize.805 22 421 276 566 15 Rainwater harvesting 1. nutrients. cotton.767 4 Improved irrigation 1. thrives on a range of soils. sorghum. Faidherbia is widespread throughout Africa. This makes Faidherbia compatible with food crop production because it does not compete for light.193 581 1.201 34 Cross-slope barriers Terracing Asia Latin America Improved irrigation Source: This study. It fixes nitrogen and has the special feature of reversed leaf phenology.428 477 2. CARBON SEQUESTRATION IN AGRICULTURAL SOILS . an Acacia species native to Africa and the Middle East.086 405 1.379 10 571 −59 1.122 33 1.34 CH A PTER 3 — META -A NA LY S ES OF SOIL CA R B ON SEQU ES TR ATION TABLE 3. millet. a characteristic that makes it dormant and sheds its leaves during the early rainy season and leafs out at the onset of the dry season. The shade provided by the trees helps in moderating microclimate and reducing crops and livestock stress and helps to improve crop yields. and water. and groundnut when grown in proximity to Faidherbia. PHOTO 3.6: Water Management and Soil Carbon Sequestration Rates (kg C ha−1 yr−1) PRACTICE MEAN LOWER 95 PERCENT CONFIDENCE INTERVAL OF MEAN UPPER 95 PERCENT CONFIDENCE INTERVAL OF MEAN NUMBER OF ESTIMATES Africa Rainwater harvesting 839 556 1. One of the most promising fertilizer tree species is Faidherbia albida. reducing losses of water and nutrients.3: Maize Growing under Faidherbia Albida Trees in Tanzania Source: World Agroforestry Centre.

and 187 Mha in 2000. their roots remaining in the soil gradually decompose.359 755 1. EC O N O M I C A N D S E CT OR WORK . Replacing annual crops with perennials increased soil carbon sequestration on average by 1 t C ha−1 yr−1 in Asia and by 0. easy to establish. During the fallow period. and fix atmospheric nitrogen.047 46 Tree-crop farming 1. Examples of species used for improved fallow include pigeon pea.35 C H A P T E R 3 — M E TA. sesban. the area under tropical plantations has increased drastically since the 1960s from 7 Million hectares (Mha) in 1965 to 21 Mha in 1980.1 t ha−1 yr−1. tropical plantations are needed for timber and. and cashew and teak plantation in Nigeria. Nitrogen-fixing plants are normally used because they are generally sturdy. The average soil carbon sequestration rate of tree-crop farming is approximately 1.204 798 1.941 71 Include trees in field 562 220 904 58 Intercropping 803 65 1. drought tolerant. Gliricidia sepium.063 7 Source: This study.5 t ha−1 yr−1).ANALYSE S OF SOIL CARBON SEQUES TR ATION Improved fallow involves the use of fast-growing trees to accelerate the process of soil rehabilitation and thereby shorten the length of fallow sequester carbon the most (about 2. more importantly. Thus. while leaf litter protects the soil from erosion. 43 Mha in 1990. as opposed to the effects of including trees where there are crops. In virtually all cases. indigenous fruit trees in South Africa. In addition to C sequestration in biomass and soil. coffee in Burkina Faso.7). the incorporation of more trees reduces spacing between crops. the plants accumulate nitrogen from the atmosphere and deep layers of the soil. The highest effects recorded in Latin America for intercropping were 1.213 6 Intercropping 1.541 17 1. while the highest effects for trees recorded in Africa was 1. enriches the soil with nutrients. Land-Use Changes The review captured diverse categories of land-use changes in Asia and Latin America compared to Africa (table 3. On TABLE 3.7: Agroforestry and Soil Carbon Sequestration Rates (kg C ha−1 yr−1) PRACTICE MEAN LOWER 95 PERCENT CONFIDENCE INTERVAL OF MEAN UPPER 95 PERCENT CONFIDENCE INTERVAL OF MEAN NUMBER OF ESTIMATES Africa Include trees in field 1. sun hemp. exotic tree species in Ethiopia.458 869 2.886 2.413 1.5 t C ha−1 yr−1 in Latin America.964 44 Improved fallow 2. as fuel for cooking. When the trees are removed after fallow. Cocoa planted at low plant density and under shade stores more carbon per unit area of soil than an equivalent area of cocoa planted at high density without shade. deep rooted.The estimates covered cocoa in Ghana and Cameroon. Intercropping examines the effects of crops on soils where there are trees.065 270 1. rubber plantation in Nigeria and Ghana. releasing additional nutrients to the subsequent crops.089 116 2. The improved fallow trees and shrubs are left in the field for several months or years. The responses over time vary in different studies and may be affected by biomass harvesting.4 t C ha−1 yr−1. Competition with crops is an important trade-off.8). and shading of crops by trees may reduce crop yields.421 14 Alley farming 1. and Tephrosia vogelii. oil palm in Cote d’Ivoire. and helps to conserve moisture.2 t ha−1 yr−1 (table 3.860 43 Asia Latin America Include trees in field Diversify trees 1. Although including the nitrogen-fixing tree Dalbergia sisso leads to more accumulation of organic carbon in the soil. the switch was to perennial grasses used as fodder for livestock.610 125 Intercropping 629 162 1.365 516 2.

135 59 Pasture-to-forest 362 −32 756 62 Crop-to-plantation 893 299 1.580 1.1 t C ha−1 yr−1. which are frequently grazed.163 619 1. The species may be similar or mixed in a manner that will generate the highest yield and biodiversity.9 t C ha−1 yr−1 in Asia and Latin America—a value comparable to that for secondary forests.4 t C ha−1 yr−1 (table 3. The establishment of pasture on cultivated land sequesters 1.094 158 Crop-to–grassland 302 −36 640 35 Exclusion or reduction in grazing 502 126 877 39 Restoration of wetlands 471 1 Annual-to-perennial 1.933 56 Crop-to-forest 528 −80 1.2 t C ha−1 yr−1 in Latin America). conversion of cultivated lands to secondary forests sequestered more than 1 t C ha−1 yr−1 in Africa. Chung. and other land uses in the continent. One greenhouse system in Taiwan had 26 crops in 4 years with high inputs of fertilizers and manures (Chang. Other studies have suggested that grassland soils may not accumulate carbon once forested and that some humid soils may even lose carbon (Paruelo et al. the conversion of native grasslands including savannahs. However. agriculture. The highest soil carbon sequestration rate for land-use change observed in this review was for intensive vegetable production in Asia (2.265 7 526 239 812 13 1. The Global Partnership on Forest Landscape Restoration estimates that over 400 Mha of degraded forest landscapes offer opportunities for restoring or enhancing the functionality mosaic landscapes of forest. 2010).392 36 Intensive vegetables and specialty crops 2. Converting grasslands to plantations in the Pampas region results in acidification of soils (Jobbagy and Jackson 2003).309 60 Asia Crop-to-forest Crop-to-plantation 878 662 1.169 315 2. and CARBON SEQUESTRATION IN AGRICULTURAL SOILS . an impact also observed in some studies of savannas in Brazil (Lilienfein et al.024 53 Grassland–to-plantation −406 −842 32 32 Exclusion or reduction in grazing Crop-to-pasture Annual-to-perennial Pasture improvement 172 −393 737 30 1. more C is sequestered when the former land use is pasture (about 1. 2000). emphasis should be placed on maximizing the use of available land by planting high-yielding tree species. This is in sharp contrast to findings for conversion of pastures to forest or plantation.129 32 932 554 1.8).8: Land-Use Changes and Soil Carbon Sequestration Rates (kg C ha−1 yr−1) PRACTICE MEAN LOWER 95 PERCENT CONFIDENCE INTERVAL OF MEAN UPPER 95 PERCENT CONFIDENCE INTERVAL OF MEAN NUMBER OF ESTIMATES Africa Crop-to-forest Pasture improvement 1. The growing of plantations on former agricultural land sequestered on average an additional 0.36 CH A PTER 3 — META -A NA LY S ES OF SOIL CA R B ON SEQU ES TR ATION TABLE 3. average. In any afforestation project.226 3. resulted in a net loss of soil carbon of 0.488 14 Latin America Pasture-to-plantation 1.549 13 Source: This study.6 t C ha−1 yr−1).004 615 1.687 825 2. In Latin America.116 −32 2. on average. to plantations.706 37 799 469 1.

Although intensified cultivation in greenhouses produced the highest average rates of soil carbon sequestration. Biochar is produced by pyrolysis.2 t C ha−1 yr−1 in Asia and Latin America. Biochar and Other Soil Amendments Of the soil amendments studied. These different practices are summarized in table 3. Application of biochar also leads to avoided emissions of nitrous oxide and methane. Grazing management and pasture improvement should be integrated for optimal benefits.9 to aid comparison. and ƒ adds nutrients and improves uptake of applied fertilizers. productive grasses) Y N Y 799 Pasture to plantation Y Y (N) 1169 Include trees (silvopasture) (N) Y Y 1167 Pasture to forest Y N (N) 362 Excluding grazing (N) N N Grassland to plantation N Y (N) Crop to grassland Y N Y PRACTICE EFFECT Source: This study. Pasture improvement sequestered 0. for example. The climate mitigation benefit of biochar lies in the fact that it decomposes more slowly and stabilizes biomass carbon. the control of animal grazing to sustain productivity and ensure continuous supply of forages to animals. thereby maintaining soil physical and chemical quality. recognizing that there is not always a clear boundary between categories of effects.37 C H A P T E R 3 — M E TA. encourages more uniform use of paddocks. Livestock grazing is relevant to many different land-use and agricultural practices. documented the consequences of intensive cultivation of high-value medicinals and aromatics in an agroforestry setting (Sujatha et al. Note: Letters in parentheses indicate typical but not absolute conditions. 2011). the thermal decomposition of biomass under limited oxygen supply and at temperatures below 700°C. and adjusts the timing of grazing. Wang 2008). has been experimented with for high-value crops in arecanut agroforestry systems (Bhat and Sujatha 2009). respectively. ƒ increases microbial biomass and activity. the differences from estimates from field or agroforestry settings were not statistically significant. the inclusion of liquid fertilizers as part of a drip irrigation system.ANALYSE S OF SOIL CARBON SEQUES TR ATION uses the appropriate mix of grass or legume species for pasture.10). biochar sequestered carbon the most (table 3. Biochar is a key ingredient in the formation of anthropogenic Amazonian dark earth (soils). One repeated-sampling design study in India. and ƒ increases mycorrhizal abundance linked to enhanced agronomic efficiency and yield.8 and 1.9: Summary of Observed Rates of Soil Carbon Sequestration (kg C ha−1 yr−1) as a Result of Land-Use Changes and Other Practices Relevant to Livestock Management GRASS PLANTED TREES PLANTED GRAZING AFRICA Pasture improvement (perennial. ƒ reduce soil and nutrient losses in runoff. respectively. Grazing management helps to ƒ maintain a healthy and productive pasture. 2010c). ƒ increase water use efficiency by increasing infiltration and reducing runoff. Increases in soil organic carbon under these high-input systems are likewise rapid (Bhat and Sujatha 2009). This study looks at livestock management practices from several perspectives. while another looked at growing vanilla orchids under different organic manure and mulch combinations in an agroforestry setting (Sujatha and Bhat 2010). As a soil amendment.7 t C ha−1 yr−1 in Africa and Latin America. biochar Grazing management. An efficient grazing system TABLE 3. But other systems included farms with organic production using no pesticides or chemical fertilizers (Ge et al. sequesters about 0.5 and 0. Its application has gained recognition in the last few years for both climate change mitigation and soil improvement. Fertigation. ƒ maintain higher amounts of soil organic matter and rapid cycling of nutrients. manages stocking rates. ƒ increases water holding capacity of the soil. EC O N O M I C A N D S E CT OR WORK ASIA LATIN AMERICA 1687 502 172 −406 302 .

2010). Fertilizers may make no net contribution to mitigation of climate change if the CO2 emitted to produce and transport them exceeds the soil storage benefit (Schlesinger. Shang et al.387 11 569 299 839 15 3. cocoa husk. In general. 2009). and Sommer 2004). They estimated a net impact of 4. a Ash. the use of biochar should ensure that crop residues and mulch needed for soil protection are not removed from the field. 2010). sawdust.67 and also by accounting for land and process emissions. intensification of agricultural production (using more fertilizers) on better lands may make less suitable land available for conversion to grasslands and forests with high soil carbon sequestration potential (Vlek. 2010).818 747 6. noted that mixtures of inorganic fertilizer and chemical fertilizers increased net annual greenhouse warming potential even further.. At the same time. (2010) calculated full GHG budgets over a 3-year period in a long-term experiment on fertilization in a double rice-cropping system in China. while process emissions are those arising from fuel and energy use (Eagle et al.237 1.11.889 6 Sulfur 425 106 743 Lime 39 1 Zinc 53 1 PRACTICE Africa Biochar a Soil amendment Asia Biochar 5 Latin America Biochar Lime 3.079 5. No significant increase in nutrient-holding capacity was observed after the addition of biochar to a coastal plain soil (Novak et al. Reducing wasteful CARBON SEQUESTRATION IN AGRICULTURAL SOILS . possibly due to increases in soil pH.303 1. and Sommer 2004). It should be noted that as much as 70 to 75 percent of fossil fuel use in the agricultural sector in the tropics is for the production and use of chemical fertilizers (Vlek. to as much as 13. Rodriquez-Kuhl.000 times longer than the residence time of most soil organic matter.38 CH A PTER 3 — META -A NA LY S ES OF SOIL CA R B ON SEQU ES TR ATION TABLE 3. Shang et al. Net Mitigation Benefits for Nutrient Management Increases in productivity from nitrogen fertilizers and irrigation need to be considered against increased emission of GHGs from soils as well as energy-related emissions.1 t CO2e ha−1 yr−1 above unfertilized controls although in terms of emissions per unit yield fertilization was still beneficial.395 8 114 −287 516 9 Source: This study. Land emissions are the differences between emissions of nitrous oxides and methane expressed in CO2 equivalents by conventional and improved practices. RodriquezKuhl. rice bran. A modeling study for Indian rice and wheat suggested that increased irrigation and fertilizer application would increase the carbon efficiency ratio even as net emissions rise (Bhatia et al. research results on biochar’s effect on some soil properties are not consistent.219 3. The estimates were derived by converting carbon sequestration rates from this study to carbon dioxide equivalent by multiplying by 3.10: Soil Amendments and Soil Carbon Sequestration Rates (kg C ha−1 yr−1) MEAN LOWER 95 PERCENT CONFIDENCE INTERVAL OF MEAN UPPER 95 PERCENT CONFIDENCE INTERVAL OF MEAN NUMBER OF ESTIMATES 2. Biochar can remain resident in the soil approximately 10 to 1. Other studies have also indicated an adverse effect of biochar application on earthworm survival. However.5 t CO2e ha−1 yr−1 above unfertilized controls. They found fertilizer plots sequestered 470 kg C ha−1 yr−1 more carbon in soil than controls but that long-term fertilization increased CH4 emissions during flooded rice and increased N2O emissions from drained soils at other times. Net Climate Change Mitigation Benefits of the Land Management Practices Estimates of the net climate change mitigation benefits of the agricultural land management practices are summarized in figure 3.

he cr co gra s op ve zin -to r c g -g ro ra ps im ss pr ov m lan ed a d n an in irri ure in nua clud gat i te lns to e t on ive -pe ree w at ve ren s er ge ni ha ta al b in rve les te rs rc tin r cr op bi opp g -to ofe ing -p r cr lan tiliz op ta er -to tio -fo n r bi est oc ha r m ch e ro ch ta em tio i n ca in l f te er ns til ifi ize ro ca r ta r es tion tio id n di m ue ve u s rs lch ifi e c s no atio co til n ve lag ot rc e he ro rs m ps o pa il a t an st m er ure ur en ra e d cin w imp em g at ro en er v ts h e cr in arv me os t e nt e in s s rcr stin clu lo op g de pe pi tre tre /bar ng e.11: Carbon Dioxide Abatement Rates of the Land Management Practices 12 10 Africa 8 6 4 2 0 18 16 14 Asia 14 12 10 8 6 4 2 0 16 Latin America 12 10 8 6 4 2 0 -2 Source: This study.ch e im mic pr al ov fe di ed rtili ve irr ze ig r r in sify ati te o ns rot n gr re ify atio as du ro n sla ce ta nd d. EC O N O M I C A N D S E CT OR WORK 39 .tio -t gr n no o-p azin or lant g re ati du on c an c nu ov ed al.er till to cro -p re er ps sid en ue n m m ial an a n pa u st age re ur m een in to-f t clu or e in de t st te r e r pa c cr es st rop opp ur e.-to.ANALYSE S OF SOIL CARBON SEQUES TR ATION FIGURE 3.es rie cr i rs op n f af far ield fo m r a es in im lley tat g pr fa ion ov rm ed in fa g ll bi ow oc ha r C H A P T E R 3 — M E TA.ing to fo r -p lan est ta ti bi on oc ha r no ica o l fe re int r re rtil sid en d ize ap ue si uce r f pl ica ma y ro d ti tio na tat ll n g io re of em n du m en ce ulc t d.

Net Mitigation Benefits for Residue Management and Tillage The net GHG mitigation potential of residue management has been assessed in a few instances. found 43 percent lower CH4 emissions in no-till rice.210 and 1. The life cycle analysis by Koga. The mitigation potential of improved irrigation is almost offset by land and process emissions. (2011) made one of the few full carbon budgets for a greenhouse system. Key constraints include controlling methane emission from rice paddies. CARBON SEQUESTRATION IN AGRICULTURAL SOILS . suggested that soil-derived CO2 emissions accounted for 64 to 76 percent of total GHG emissions. but they obviously depend a lot on high levels of inputs as well. but crossslopes/barriers achieve moderate mitigation impact. The Biomass Is Smaller Compared to that of Agroforestry Systems Source: Curt Carnemark/World Bank.40 C H A PTER 3 — META -A NA LY S ES OF SOIL CA R B ON SEQU ES TR ATION fertilizer use by ensuring that applied rates do not exceed crop requirements is an important mitigation strategy. (2010). 2010). Sawamoto.3 times in tropical areas. The conversion from conventional agriculture enhances carbon sink potential as much as 8 times in temperate and 1.4: Crop Harvesting in Mali. in the other provinces. The GHG mitigation benefits of residue management also require consideration of processes apart from soil carbon sequestration. Improved management of compost processes and mulches can reduce non-CO2 emissions (Zeman. Wang et al. and Shindo (2007). the total net mitigation potential at soil saturation was equivalent to just 1. Returning straw to fields rather than burning it helps avoid emissions associated with producing synthetic fertilizer as well as CH4 and N2O emissions from burning (Lu et al. respectively. Net Mitigation Benefits of Intensification and Water Management Very intensive systems such as vegetable production under greenhouses can sequester a lot of carbon in the soil. Japan. and Rich 2002). The net potential of straw return (rather than burning) in China was assessed using a GHG budget model by Lu and et al. The experimental study by Harada. for example. and Tsuruta (2006) of conventional and reduced tillage in intensive cropping systems in Hokkaido. Their analyses suggest that greenhouses are a net sink of 1. straw return increased net GHG emissions. Kobayashi. emphasizing the importance of soil management practices. They found that across 10 provinces. PHOTO 3.230 kg C ha−1 yr−1 in temperate and subtropical areas. Adoption of reduced till in these systems was expected to reduce total GHG emissions by 4 to 18 percent for various crops as a result of slower decomposition rates and fuel saving for plowing. Depken.7 percent of the fossil fuel emission budget in China for 2003.

K. Wilcke. S. R. C. Eagle. 2000. For example.. 2009. R. C. R. “Soil Fertility and Nutrient Uptake by Arecanut (Areca catechu L. Bhat. “A Review of Nitrogen Fertilizer and Conservation Tillage Effects on Soil Organic Carbon Storage. Wassmann et al. 2005).” Soil Use and Management 21: 38–52. R. and Sujatha.” Biogeochemistry 64: 205–229.. and Iwasaki. M.and below-ground sequestration rates at the same time and possible trade-offs or interactions between them. Frolking.. C.” Mitigation and Adaptation Strategies for Global Change 11: 403–427... midseason drainage is a viable practice in some locations in India to reduce CH4 emissions (Babu et al. N. Nie. H.. 2006.. 2006... Shindo. L. B. Pathak 2010. H. 2007. Sawamoto. “Soluble Organic Nitrogen Pools in Greenhouse and Open Field Horticultural Soils Under Organic and Conventional Management: A Case Study. K. “Reduction in Greenhouse Gas Emissions by No-Tilling Rice Cultivation in Hachirogata Polder. 2003. “Assessing Greenhouse Gas Emissions Production in China Over the Environmental Quality 35 (4): Lilienfein. 2006. 2006. 2007. and Zheng et al. and Cover Crops to Supplant Crop Residue Carbon in Corn Stover Removed Cropping Systems.” Soil Science & Plant Nutrition 54: 587–599. A.. Northern Japan: Life-cycle Inventory Analysis.) as Affected by Level and Frequency of Fertigation in a Laterite Soil. 2000. Ayarza. W. “Soil Acidification in Pinus Caribaea Forests on Brazilian Savanna Oxisols.. 2010. Y. Duke University. Harada. Aggarwal.. Li. Koga. “Use of Manure. 2006. Net Mitigation Benefits for Agroforestry and Land-Use Changes The impacts of land-use changes to trees are positive and large. and Zech.. “Patterns and Mechanisms of Soil Acidification in the Conversion of Grasslands to Forests. Thelen. . and Jackson..” Journal of 1554. R..” Agronomy Journal 100 (6): 1703–1710. Babu et al. L..g. but precise estimates were not possible given the paucity of data... H. Li et al.. such as to agroforestry or plantations. Olander. 2005a. The effects of some practices such as excluding grazers from rangelands or grasslands are.” Nutrient Cycling in Agroecosystems 86. Rose. Xiao. Pathak. H. P. Alvarez. E. Sohi et al.. and Mawdesley. One estimate for humid tropics globally suggested that tree-based agroforestry systems could sequester 70 Mg C ha−1 in vegetation and up to 25 Mg C ha−1 in the topsoil (Mutuo et al. Jain. Land-use changes away from cropping.. Wu. 413–424.. Vilela. Net Mitigation Benefits for Biochar Application Applications of biochar or charcoal.. McDonald. 2005b.. G. E. K.. P.. The timeaveraged above-ground biomass of crops is small and does not accumulate easily. Other more complex water management strategies have been proposed and demonstrated to reduce CH4 emissions (Minamikawa and Sakai 2007).” Soil Science and Plant Nutrition 52 (4): 564–574. S. Chung. Lima. DeAngelo. D. A... 2006..” Agricultural Water Management 96: 445–456. Gaunt. Increasing fertilizer use increased both yields and CH4 emissions. however. M. Wang. Most of the potential impacts of changes in agricultural practices on carbon stocks are by definition below ground. T. J. Gardner. 2010c.. Alvarez. J.... Alternatives for Mitigating Net and Increasing Yields from Rice Next Twenty Years.. EC O N O M I C A N D S E CT OR WORK 41 Babu. W.” Soil Science and Plant Nutrition 53 (5): 668–677. Tripathi.” Soil Use and Management 21: 38–52. N. 2008.. Technical Working Group on Agricultural Greenhoused Gases (T-AGG) Report. Li.. Tsuruta. REFERENCES Acharya. J. N. Ge. Salas.ANALYSE S OF SOIL CARBON SEQUES TR ATION A critical issue for soil carbon sequestration activities across humid parts of Asia is how to reduce emissions of CH4 from rice fields. Nicholas Institute. Bhatia. Minamikawa and Sakai 2005. 2010.” Forest Ecology and Management 128: 145–157. fairly small. Chang. Tong. H. and Robertson. E.C H A P T E R 3 — M E TA.. B. Kobayashi. “Biochar Sequestration in Terrestrial Ecosystems—A Review.. H.” European Journal of Soil Biology 46: 371–374. Haugen-Kozrya. resulted in higher overall GHG mitigation potential than other practice changes reviewed in this study. on average... 2007). Compost. S. Adhya. These findings are consistent with reviews that suggest potential value of biochar for improving soil conditions and increasing sequestration of GHGs (Lehmann et al. “Trade-Off Between Productivity Enhancement and Global Warming Potential of Rice and Wheat in India. Greenhouse Gas Mitigation Potential of Agricultural Land Management in the United States: A Synthesis of the Literature. H. M. Lehmann. 2008. “Effect of Different Types of Organic Fertilizers on the Chemical Properties and Enzymatic Activities of an Oxisol Under Intensive Cultivation of Vegetables for 4 years.. T. S. Hong. D. and Rondon.P. Millar. 2006). Durham. Y. W. Naya. S. Jobbagy. Northern Japan.. T. L.. K. “Nutrient Losses From Rain-Fed Bench Terraced Cultivation Systems in High Rainfall Areas of the MidHills of Nepal. “A Review of Nitrogen Fertilizer and Conservation Tillage Effects on Soil Organic Carbon Storage. Fronning.. and Min. Henry... provide more compelling examples where it is useful to think of both above. F. R. J. 2010).. “Field Validation of DNDC Model for Methane and Nitrous Oxide Emissions From Rice-Based Production Systems of India.” Land Degradation & Development 18: 486–499. There is a very large scientific literature on factors influencing emissions and management options (e.” Nutrient Cycling in Agroecosystems 74: 157–174. 2006. “Life Cycle InventoryBased Analysis of Greenhouse Gas Emissions From Arable Land Farming Systems in Hokkaido. G.

” Soil Science 174: 105–112. 1427–1434. S.. Altesor. and Desjardins. M. Liu.. Zhang. and Sommer. D.” Agriculture.. “Quantifying the Reduction of Greenhouse Gas Emissions as a Result of Composting Dairy and Beef Cattle Manure. Zhang. B.” Rangeland Ecology & Management 63: 94–108.42 C H A PTER 3 — META -A NA LY S ES OF SOIL CA R B ON SEQU ES TR ATION Liniger. L.. Xu. T. A. Wang. Lezama.” Nutrient Cycling in Agroecosystems 72: 173–187.. Chang. and Environment 140: 234–244.. Lu. Li. and Bhat. M. 2011. 2007. “Carbon Stocks and Fluxes in Rangelands of the Rio de la Plata Basin.. R. Watts.” Global Change Biology. Sujatha. 2010.. Environmental Pollution 159. Matsumoto. P.. and Balasimha. “Mitigating Greenhouse Gas and Nitrogen Loss With Improved Fertilizer Management in Rice: Quantification and Economic Assessment. E..... Trzcinski.” Nutrient Cycling in Agroecosystems 71: 43–54. 2009. “Research on How the Composting Process Impacts Greenhouse Gas Emissions and Global Warming. “Effect of Long-Term Fertilization on C Mineralization and Production of CH4 and CO2 Under Anaerobic Incubation From Bulk Samples and Particle Size Fractions of a Typical Paddy Soil. and M. 2008. M. “Characterization of Methane Emissions From Rice Fields in Asia III: Mitigation Options and Future Research Needs. B. Bhat... J. W.. P.. Palm.. B. Wu. Sustainable Land Management in Practice . F... Wu... Mekdaschi Studer. X.. Duan. J. J. Cadisch... and Lu.. 2005. Ecosystems. Krull. Zhu.. “On Fertilizer-Induced Soil Carbon Sequestration in China’s Croplands. Sujatha.” Nutrient Cycling in Agroecosystemes 87: 443–454. G.. doi: 10. K. 2010. F.1111/j. H. C. Niu.. Ecosystems.. C. “Net Mitigation Potential of Straw Return to Chinese Cropland: Estimation With a Full Greenhouse Gas Budget Model.” Journal of Agricultural Science 147 (1): 31. 2003. and Oesterheld..” Ecological Applications 20 (3): 634–647. Han.. J. Q. “Impact of Biochar Amendment on Fertility of a Southeastern Coastal Plain Soil. and Hakamata.. W.. Sumberg. Gurtner. X. K. J.. G. Yang. X. Baeza.. Zhang. Pineiro. S. L. D. and Guo. and Sustainability 6: 213–233. and Li. L.. “Energy Use and CO2 Production in Tropical Agriculture and Means and Strategies for Reduction or Mitigation. Peng.. Zeman.. and Rich..” Agriculture. 2010... 2000. and Niandou. H. 2011. Y. D. and Pan. Xu. Chen. Paisancharoen. H. Ge. R. L.. J.. Novak.. K. 2010. Zheng. Wassmann. R.. M. H. Quantification of net carbon flux from plastic greenhouse vegetable cultivation: A full carbon cycle analysis. Y. Ahmedna. M. 2010..” Global Change Biology 16: 849–850. Ouyang. G.. J. Gu.. S. Ecosystems... M.” Soil Science and Plant Nutrition 54: 277–288. P.” Advances in Agronomy 105:47–82. F. E. Fang. G. C. 2010. Y. Pattey. and Bol. C. Y. “Net Annual Global Warming Potential and Greenhouse Gas Intensity in Chinese Double Rice-Cropping Systems: A 3-Year Field Measurement in LongTerm Fertilizer Experiments. C. Velazquez-Garcia. N. Lantin. Depken. Z. “A Review of Biochar and Its Use and Function in Soil... “Residue Removal and Climatic Effects on Soil Carbon Content of No-Till Soils.) Plantations in India.. Baldi... A. Laird. W. Potter. Zhou.. Busscher. “Impact of Intercropping of Medicinal and Aromatic Plants With Organic Farming Approach on Resource Use Efficiency in Arecanut (Areca catechu L..” Agricultural Water Management 97: 988–994.. Minamikawa. J. X. 2010. S.. C. 2004. J. Neue. M. M.. Yang.1365-2486. and Environment 120: 129–138. E. Rodriquez-Kuhl. X.. A.. 2005. R.” Journal of Soil and Water Conservation 62: 110–114... Mutuo... 2009. Shen. P. P. and Zhang. R.. Gao. “The effect of Water Management Based on Soil Redox Potential on Methane Emission From Two Kinds of Paddy Soils in Japan. Buendia.” Agriculture.” Industrial Crops and Products 33: 78–83. Q. Vlek. Liu.. M. K. Pathak. 2005. “Potential of Agroforestry for Carbon Sequestration and Mitigation of Greenhouse Gas Emissions From Soils in the Tropics. R. L.) Intercropped in Arecanut to Irrigation and Nutrition in Humid Tropics of India.. H.. Paruelo. C. and Torbert. X. 2011. Zou. Luo... Kannan. Development... “Minor Stimulation of Soil Carbon Storage by Nitrogen Addition: A Meta-Analysis. Y. X.. Sohi S. and Verchot. H. Lopez-Capel. T. “Toward a Disaggregated View of Crop–Livestock Integration in Western Africa.. World Overview of Conservation Approaches and Technologies (WOCAT) and Food and Agriculture Organization of the United Nations (FAO).Guidelines and Best Practices for Sub Saharan Africa. Y. G. 2011. H. “Long-Term Effects of Manure Application on Grain Yield Under Different Cropping Systems and Ecological Conditions in China. Xu. and Zheng.. H. “Response of Vanilla (Vanilla Planifolia A. A. Shang. R.. and Environment 107: 397–407. CARBON SEQUESTRATION IN AGRICULTURAL SOILS . Albrecht.” Compost Science & Utilization 10 (1) : 72.. Schlesinger. R.” Environment. Lu. Hauert. E. and Sakai.” Land Use Policy 20: 253–264. H. 2002. Corton. “Carbon Balance in Maize Fields Under Cattle Manure Application and NoTillage Cultivation in Northeast Thailand. 2007. D.. Y.” Nutrient Cycling in Agroecosystemes 58: 23–36. Wang. Scopel. S. J.

which is highly resistant to microbial decomposition (figure 4. easily obtainable inputs to estimate soil carbon. RPM = resistant plant material. ranging from highly labile to inert materials. monthly open pan evaporation.1: Representation of the RothC Model Organic inputs RPM IOM DPM HUM HUM CO2 BIO BIO CO2 BIO HUM CO2 Source: This study. Both DPM and RPM decompose to form CO2. BIO = microbial biomass. and HUM. Note: DPM = decomposable plant material. and inert organic matter (IOM). HUM = humified organic matter. resistant plant material (RPM). clay content of the soil. humified organic matter (HUM). average monthly mean air temperature (in degrees Celsius). BIO.1). The pools have different susceptibilities to decomposition.C H A P T E R 4 — E C O SYST E M SIMUL AT ION MODE L ING OF S OIL CA R B ON SEQUES TR ATION Chapter 4: 4.1 43 ECOSYSTEM SIMULATION MODELING OF SOIL CARBON SEQUESTRATION MODEL DESCRIPTION The RothC model (Coleman and Jenkinson 2008) was used to project the amount of soil carbon sequestered by different land management practices up to 2035. EC O N O M I C A N D S E CT OR WORK . and an estimate of the decomposability of the incoming organic FIGURE 4. The pools include easily decomposable plant material (DPM). One of the main advantages of the RothC model is its requirement of a few. The proportion that is converted to CO2 and to BIO plus HUM is primarily determined by the clay content of the soil. The RothC model describes the fate of organic inputs entering the soil environment. The required inputs are monthly rainfall. and HUM. microbial biomass (BIO). IOM = inert organic matter. BIO. and the release of CO2. Subsequent further decomposition of the BIO and HUM produces more CO2. the undergoing decomposition within the soil biomass to form a number of carbon pools.

Y = Y0(1 − e−abckt).60e−0. A is the activity data or land area (in ha) where a given sustainable land management practice was adopted. modeling FAO Crop Calendar—a crop production information tool for decisionmaking (FAO 2010): http://www. Harmonized World Soil Database (version 1.1: FAO/IIASA/ISRIC/ISSCAS/JRC. Rome.fao.do Direct manure/composted manure input data Carbon input for modeling Global Fertilizer and Manure Application Rates. Equations for calculating each of these factors can be found in Coleman and Jenkinson (2008). decomposition rates (BIO plus HUM) pools formed during decomposition using the following exponential equation: The amount of carbon (Y) that decomposes from an active pool in a given month can be represented by an exponential decay function of the form where x is the ratio CO2/(BIO + HUM) and BIO and HUM are the corresponding biomass and humic pools formed initially as incoming plant materials. The RothC model also adjusts for clay content by altering the partitioning between evolved CO2 and soil C x = 1. Land Use and the Global Environment.iiasa. Austria. and f the emission factor is the sequestered carbon in t C ha−1 yr−1. http://www. McGill University Carbon input data for agroforestry and cover crops From several published literature See references Land-use systems Additional data used to estimate land area for which a given technology is applicable FAO Land Use Systems http://www.67(1.1).1: Spatial Datasets Used in the Study DATA PURPOSE REFERENCES Clay content. The harvested areas of eight major crops (barley. rice. Environment and Natural Resources Service— Agrometerology Group Crop calendar RothC model parameterization. Italy and IIASA.home http://www. others related to the input of carbon such as crop yields.at/Research/LUC/External-World-soildatabase/HTML/index. Harvested area and Yields of 175 crops (M3-Crops Data). Department of Geography. [1] where Y0 is the initial amount of carbon in the particular pool. Laxenburg. pulses. and wheat) occupying more than 70 percent of the global agricultural area were estimated within a geographical information system and used for modeling. McGill University. TABLE 4. CARBON SEQUESTRATION IN AGRICULTURAL SOILS .1). While the above factors contribute exponentially to the soil carbon remaining at the end of each month.html Temperature and precipitation RothC model parameterization FAOCLIM 2. University of Wisconsin Source: This study. World-wide Agro Climatic Data Base. Land Use and the Global Environment. k is the yearly decomposition rate constant for that particular compartment.44 CHAP T E R 4 — EC OSY S TEM SIMULATION MOD ELING OF S OIL CA R B ON SEQU ES TR ATION material referred to as the DPM/RPM ratio (Coleman and Jenkinson 2008). Food and Agriculture Organization of the United Nations. [3] where Cs is the change in soil organic carbon as a result of adoption. initial soil carbon content RothC model parameterization Harmonized World Soil Database v 1.fao.aspx#ancor Harvested area (ha) of selected crops and crop yield (t/ha/year) data Carbon input for modeling Harvested area and yields of selected crops. [2] The global soil carbon mitigation potential due to the adoption of sustainable land management practices was modeled to a depth of 30 cm using the following relationship: Cs = A × f. Navin Ramankutty. b is the ratemodifying factor for soil moisture. The model has been validated across the agro-ecological zones of the world and has been used for many subnational and national GHG inventories.org/geonetwork/srv/en/metadata.org/site/569/default.85 + 1.org/geonetwork/srv/en/main. sorghum. c is the rate-modifying factor for soil cover.0786%clay). soybean.ac. Food and Agriculture Organization of the United Nations livestock data for Africa.fao. root biomass. 2009: http://faostat. maize. millet. The activity data (global cropland area) were derived from available spatial datasets (table 4.org/agriculture/seed/cropcalendar/welcome.fao. and t = ¹⁄¹² is to scale k into monthly values. Department of Geography. FAO. and the proportion of carbon in plant residues are linearly related to the amount of carbon decomposing. a is the rate-modifying factor for temperature. 2009.show Sustainability and the Global Environment Global Agro-Ecological Zones Stratification of Africa Center for Sustainability and the Global Environment.

2006). and 75 percent) were modeled. FIGURE 4. a common practice is to burn or remove the residues from the field.3). For each stratum and region. Crop yields and manure were converted into organic residues as model inputs using IPCC standard equations (IPCC.25 was assumed.e. As a result.. and maize-soybeans systems are dominant in several parts of South America.org/agriculture/seed/ cropcalendar/welcome. ƒ The typical land management practices associated with the cropping systems.2. 25 percent. cropping systems in South Asia are dominated by rice. Asia. where a ratio of 0. The choice of the suitable mitigation scenarios for each world region was guided by the following baseline considerations: ƒ The most dominant cropping systems in a specific region.2). the global cropland extent was stratified into mapping units based on temperature. residue management.fao. ƒ Documented impact of agricultural land management practices on carbon sequestration (see Chapter 3). manure management. and clay content. most of the farming systems in North America already leave the residues on the field. the most dominant cropping systems were identified from the literature. different fractions of retained residues (i. North America. cowpea. The specific organic inputs for the land management practice being modeled were set on a monthly basis using crop calendars specific for each stratum. mixed smallholder farming systems are the dominant system in Africa.44 was set for modeling sustainable land management scenarios except for agroforestry. For instance.2: The 12 Strata Used for Ecosystem Simulation Modeling Source: This study. The land management practices include integrated residue and manure management. A summary of the farming systems is given in Appendix 4.1. This resulted in 12 distinct clusters (strata) within eight regions (Africa. Central America. For example. Oceania. A detailed description of the scenarios for Africa is provided in Appendix 4.C H A P T E R 4 — E C O SYST E M SIMUL AT ION MODE L ING OF S OIL CA R B ON SEQUES TR ATION Using cluster analysis. 50 percent. EC O N O M I C A N D S E CT OR WORK 45 .do) to model carbon sequestration under various levels of organic inputs for Africa. and integrated fertility management were modeled. A detailed description of the baseline and mitigation scenarios is provided in Appendix 4.1. land rehabilitation. and groundnut as cover crops. The study also took advantage of the recently released crop calendar for Africa (http://www. coppice and improved fallow. Russia. To account for trade-offs between mulch residues and livestock and fuel biomass. agroforestry. agroforestry systems including perennial crops. tillage management. A standard DPM/RPM ratio of 1. precipitation. and cropping systems involving mucuna. Africa was classified into four agroecological zones using procedures similar to the global cropland extent (Figure 4. while in Africa. Europe. and South America) (Figure 4.

v-c-s. 4. Information on carbon sequestration potential of a location can be derived by point-and-click or by searching using place name.org/ sites/v-c-s. The procedures are provided in Appendix 4.esd.org/files/SALM%20Methodolgy%20V5%20 2011_02%20-14_accepted%20SCS.000 land management scenarios carefully chosen to reflect situations typically encountered in agricultural projects. worldbank. CARBON SEQUESTRATION IN AGRICULTURAL SOILS . The Internet GIS database provides per-ha estimates of soil carbon sequestration under different land management practices for a period of 20 to 25 years (figure 4.org/SoilCarbonSequestration/. The tool includes over 4.4). Users can download data from the Internet database and integrate with other GIS information to estimate soil carbon stock changes for different agricultural projects.3.3: Africa Agroecological Zone Uncertainties in model parameters were estimated following the adoption of the Sustainable Agricultural Land Management (SALM) methodology (http://www.pdf).46 CHAP T E R 4 — EC OSY S TEM SIMULATION MOD ELING OF S OIL CA R B ON SEQU ES TR ATION FIGURE 4.2 RESULTS Soil Carbon Sequestration Internet Tool Modeling results are summarized in an Internet geographical information system (GIS) tool at http://www.

Soil Carbon Loss Under Low Input Baseline Scenario The predicted cumulative C loss by 2030 varies for different cropping systems and regions of the world. The highest sequestration potentials for direct and composted manure (550 and 587 Mt. cumulative carbon sequestration by 2030 varies from 0. rice. The highest cumulative sequestration for green manure (6 to 10 t C ha−1) are predicted for Europe and North America.2). EC O N O M I C A N D S E CT OR WORK Figure 4. The lowest amount of sequestered carbon from cover crops was recorded for Middle America (15 Mt). Composted manure sequesters slightly higher than direct manure (0.5 Million tons (Mt) C for soybean to 37 Mt C for maize (figure 4. pulses. Agroforestry by far has the highest sequestration potentials for all world regions. under pulses for South America (26 t C ha−1).esd. The highest emphasis should be placed on agroforestry systems because of the diverse benefits they provide including compatibility of some tree species with crops and livestock production.worldbank. its estimates markedly suffer from lack of good resolution spatial data of no-tillage adopting areas. respectively) were observed for North America. Carbon sequestration potential of the land management practices is in the order of agroforestry > cover crops > manure > crop residues > no-tillage. The loss is highest for Russia under wheat. No-tillage sequesters least (0.3 t C ha−1).04 to 14 t C ha−1 versus 0. The spatial patterns of composted and direct manure are similar because both models are based on frequency of livestock. and barley (35 to 40 t C ha−1) where the drive to exploit minerals and other natural resources has spread agriculture to unproductive soils and low fertilizer use has led to a sharp decrease in soil fertility. while the highest was recorded for Asia (1 Gigaton). Agroforestry is also vital for the restoration of marginal and degraded lands.6 reveals differences in the predicted spatial pattern of carbon sequestration for the land management practices. In Asia. and under millet for Europe (23 t C ha−1). The highest cumulative C loss under the low input scenario occurs under rice and pulses for Africa (20 t C ha−1). Carbon Sequestration Maps Soil Carbon Sequestration Under Different Land Management Practices Carbon sequestration through residue management depends much on the land area devoted to a given crop (table 4. while the highest for maize residue (7 to 12 t C ha−1) are predicted for Asia.02 to 13 t C ha−1).4: A Screen Shot of the Soil Carbon Internet Database Source: http://www. The cumulative C loss is around 15 to 20 t C ha−1 for all cropping systems in Asia. High sequestration rates are generally observed in the Guinea savannah areas in Africa for most of the practices. while Russia has the least (less than 0. 47 . Based on the assumption of 50 percent residue retention. Middle America is predicted to experience the next highest loss due to depletion of crop residues in virtually all its cropping systems (25 to 37 t C ha−1).2 Mt).C H A P T E R 4 — E C O SYST E M SIMUL AT ION MODE L ING OF S OIL CA R B ON SEQUES TR ATION FIGURE 4. and suitability of certain tree species for bioenergy. The time-averaged above-ground biomass of trees is relatively large compared to crops. the sequestered carbon varies from 10 Mt for millet to 517 Mt for rice. increased income through production of indigenous fruit trees.08 to 1.org/SoilCarbonSequestration/.5).

5: Cumulative Soil Carbon Loss by 2030 Assuming 15 Percent Residue Retention (t ha−1) Under Different Cropping Systems Wheat 0 Middle South North Russia America America America Europe Asia Africa Oceania 0 –5 –5 –10 –10 –15 Soybean Africa Oceania –15 –20 –20 –25 –30 –25 –35 –30 –40 –35 –45 –40 0 Middle North South America America Europe America Asia Middle America South North America America Sorghum Asia Africa Rice Oceania 0 Middle South North Russia America Africa Europe America Asia America Oceania –5 –5 –10 –10 –15 –15 –20 –25 –20 –30 –25 –35 –40 –30 Millet Europe Asia North America Middle South America Africa America Asia Africa 0 North Maize Europe America Oceania 0 –5 –5 –10 –15 –10 –20 –15 –25 –30 –20 –35 –25 –40 Pulses 0 Middle North South Russia America America AmericaEurope Africa Asia Oceania –5 –10 Barley 0 Middle South North Russia America AmericaEurope America Asia Africa Oceania –5 –10 –15 –15 –20 –25 –20 –30 –30 –35 –40 –35 –45 –45 –25 –40 Source: This study. CARBON SEQUESTRATION IN AGRICULTURAL SOILS .48 CHAP T E R 4 — EC OSY S TEM SIMULATION MOD ELING OF S OIL CA R B ON SEQU ES TR ATION FIGURE 4.

EC O N O M I C A N D S E CT OR WORK 1.552 6.799 3.000 12.744 – 9.743 0 1.500 3.439 – 6.479 3.480 – 9.339 – 12. Maize Source: This study.49 C H A P T E R 4 — E C O SYST E M SIMUL AT ION MODE L ING OF S OIL CA R B ON SEQUES TR ATION FIGURE 4.338 9.342 – 5.438 12.500 3.014 – 3.553 – 4.916 – 6.563 – 3.000 6.6: Predicted Cumulative C Sequestration for Different Land Management Practices by 2030 Green Manuring Agroforestry 2030 2030 Tons per Hectare Tons per Hectare 2.000 12.860 – 23.000 6.000 9.000 Kilometers .915 3.859 4.341 5.000 9.976 6.000 Kilometers 0 Non Tillage Composted Manure Direct Manuring Residue Management.

2: Modeled Cumulative Soil Carbon Sequestration Potential by 2030 (Mt C) Under Different Land Management Practices AFRICA ASIA EUROPE MIDDLE AMERICA NORTH AMERICA OCEANIA RUSSIA SOUTH AMERICA Residue management Barley 7.rothamsted. and Jenkinson. and Other Land Uses. ed.890 478.233 Wheat No-tillage Agroforestry 1.731 4. Intergovernmental Panel on Climate Change. K.402 772. S.574 Millet 10.557 7.524 35.pdf. UK.727 632.511 2416.721 1309. A Model for the Turnover of Carbon in Soil: Model Description and Windows Users Guide..ac.608 727.562 Soybean 0.106 5.460 586.556 2. Institute for Global Environmental Strategies.237 1009.504 360.700 0.434 803.966 20.064 57.101 203.703 23. 2006.128 0. REFERENCES Coleman.50 CHAP T E R 4 — EC OSY S TEM SIMULATION MOD ELING OF S OIL CA R B ON SEQU ES TR ATION TABLE 4. Forestry.907 18.281 209. Japan.uk/aen/carbon/mod26_3_ win.995 Rice 17.229 19.082 14.131 136.868 210. Ngara. Tanabe. Eggleston.2008 ROTHC-26.843 Sorghum 21. H. Miwa.359 Maize 37.898 16.657 9.” in 2006 IPCC Guidelines for National Greenhouse Gas Inventories. K. Harpenden.209 Cover crops 513. Available online at http://www.637 3.193 48.120 34. D.098 Composted manure 427. Agriculture.494 11.218 0. and K.495 Source: This study.771 516.993 Pulses 13. Buendia. “Volume 4. Rothamsted Research. T.763 33.279 33. L. S.558 1.252 549.361 81. CARBON SEQUESTRATION IN AGRICULTURAL SOILS .080 20.664 32.740 0.415 Direct manure 400.3.

Afforestation and pasture establishment on degraded land with relatively high mitigation potentials are modestly profitable. while the area of each column equals the cost or benefit of adopting the practice. Alley farming and intercropping also yield relatively high profits in Africa.1 also reveals the inherent trade-off between the profitability of the land management practices and their mitigation potentials. all possible costs and benefits that would accrue to the farmers were valued at market prices the farmers are likely to face in switching to the practices. it both reduces emissions and saves money). For the private MACs. Computed public costs EC O N O M I C A N D S E CT OR WORK included investments in seeds and seedlings. so only the curves for the A1b scenario are presented. The MAC curve analysis was a quantitative assessment of all possible costs and benefits that would accrue if the various management practices were implemented. and contribute additional GHGs in the atmosphere. Such analysis helps in identifying potential mitigation pathways for a given context. The public costs of all the land management practices are lower than US$20 per ton of GHG mitigated in Africa. and Latin America.51 C H A P T E R 5 — E C O NOMICS OF SOIL CARBON SE QUESTR ATION Chapter 5: 5. on the other hand. poor agricultural land management will intensify land degradation. Asia. The MAC is plotted on the y-axis and GHG abated on the x-axis.1).11) were used to scale-up for each continent by multiplying by the suitable areas for each practice within a continent in 2030. but to varying degrees (table 5. while positive MACs imply that the land management practice reduces emissions at a cost and thus requires judgment against the cost of inaction. Moving along the curve from left to right worsens the cost-effectiveness of the mitigation measures.1 shows the MACs for Africa. The costeffectiveness of the land management practices in mitigating climate change has been evaluated using the marginal abatement cost (MAC) curve. The abatement rates of the land management practices (figure 3. This suggests that farmers may be reluctant to privately implement land rehabilitation. Afforestation and grassland rehabilitation cost governments more than $20 per ton of GHG mitigated in Asia and Latin . All the land management practices are profitable to the farmer. The shapes of the curve are similar across scenarios. and other administrative costs.1 ECONOMICS OF SOIL CARBON SEQUESTRATION MARGINAL ABATEMENT COSTS Sustainable land management technologies can generally be deployed at varying costs. With the exception of Asia. The width of the column is the amount of GHG mitigated by the land management practice. manure and fertilizer with modest mitigation potential yielded relatively high profits.1. A MAC curve depicts the relationship between the cost-effectiveness of different land management practices vis-à-vis the amount of GHG abated. extension services. Table 5. input subsidies. The public costs. The adoption period was assumed to be 25 years. The cost-benefit flows were discounted to present value to calculate NPV using a discount rate of 9 percent. Negative MACs indicate that a land management practice is self-financing (that is. refer to government support toward the implementation of land management practices. Efforts were made to avoid double counting as some of the practices are mutually exclusive. The assumptions for estimating the suitable areas for the four IPCC special reports on emission scenarios are described in Appendix 5. creating the need to evaluate their cost-effectiveness. Figure 5. In this study. Without public support to farmers. On the other hand. increase farmers’ vulnerability. the time carbon sequestration reaches saturation for most of the land management technologies. with the land management practices ranked against the MAC from the lowest to the highest. The MAC curve can also be used for cost-benefit analysis by comparing the unit mitigation cost with the shadow price of carbon or the cost of purchasing emissions allowance. private and public marginal abatement costs were computed. The marginal benefit of no-tillage is greater than US$100 per tonne of carbon dioxide mitigated for the three regions. the marginal benefit of residues for the regions is modest (less than US$50).

000 1.500 2.500 0 0 100 200 300 400 500 600 700 800 –100 Cover crops Grassland to plantation –800 Pasture to forest Crop to forest Diversify trees Inculde-trees Rainwater harvesting Pasture to plantation Intensify rotation Application of manure Intercropping Biochar –1.500 2.500 0 1.000 1.000 2.000 0 4.600 Residue management Diversify rotation marginal abatement cost ($/t CO2) marginal abatement cost ($/t CO2) 0 –200 Pasture improvement –300 Rainwater harvesting –400 Manure Annual to perennial –500 –600 –700 Pasture on degraded land Reduced grazing No tillage Improved irrigation scenario A1b-Latin America cropland Improved irrigation scenario A1b–Latin America grassland Source: This study.000 0 –100 Intensive vegetables –400 Biochar –600 Improved irrigation Alley farming –800 Crop to forest Manure Organic soil restoration –1. CARBON SEQUESTRATION IN AGRICULTURAL SOILS .200 Crop to plantation Cover crops Rainwater harvesting –1.000 0 –25 Include trees –100 Slope/Barriers marginal abatement cost ($/t CO2) marginal abatement cost ($/t CO2) 0 500 Residues –200 Cover crops Afforestation Inorganic fertilizer –400 Rotation diversification Rainwater harvesting Other soil ammendments Biochar –500 Improved fallow Rotation Intensification Manure Alley cropping Intercropping –300 Tree-crop –50 Water management –75 Grazing management Improved pastures –100 Manure –125 Pasture established degraded land –150 –175 –200 –225 Fertilizer –600 No tillage –250 scenario A1b-Africa cropland scenario A1B-Africa grassland CO2 abated (Mt yr–1) CO2 abated (Mt yr –1) 0 3.000 Intensify rotation No tillage Biofertilizer Inorganic fertilizer –1.1: The Private Marginal Abatement Cost Curves CO2 abated (Mt yr –1) 0 500 Mt CO2 abated 1.000 1.52 C H A PTER 5 — EC ONOMIC S OF SOIL CA R B ON SEQU ES TR ATION FIGURE 5.000 0 1.000 cummulative CO2 abated (Mt yr–1) 1.400 marginal abatement cost ($/t CO2) –200 marginal abatement cost ($/t CO2) 500 –200 Pasture on degraded land –300 Crop to grassland –400 –500 Improved irrigation –600 –700 Annual to perennial Reduced grazing Manure –800 Residues –900 Fertilizer scenario A1B-Asia cropland scenario A1b-Asia grassland Rainwater harvesting cummulative CO2 abated (Mt yr–1) 0 500 1.000 1.

manure. inorganic fertilizer. pasture improvement. afforestation. Asia (US$16. while total public costs range from $20 billion in Africa to $160 billion in Asia. pasture improvement Pasture on degraded land No-tillage. biochar. grassland–to-plantation. intensify rotation. afforestation. pasture to forest. organic soil restoration. pasture on degraded land. Total private profits range from US$105 billion in Africa to $1.5 billion). The total mitigation potential varies from 2. afforestation. while in Latin America. terracing. Conversely. alley farming. rainwater harvesting. other soil amendments. EC O N O M I C A N D S E CT OR WORK .3 Gt CO2-eq for Latin America to 7. attempts to increase soil carbon storage through afforestation may reduce productivity (profitability). biofertilizer. manure. The total cost for afforestation was highest for Africa (US$2. TABLE 5. intercropping.7 million). while the lowest total public cost was for terracing in Africa (US$18. tree crop farming. pasture. diversify rotation. biochar. grazing management. afforestation.2 TRADE-OFFS IN SOIL CARBON SEQUESTRATION Trade-off is inherent in the attempt to achieve the triple wins of food security. pasture establishment on degraded land Latin America No-tillage. rainwater harvesting No-tillage. include trees.4 trillion in Asia. pasture on degraded lands Manure No tillage. America (table 5.3). manure. intercropping. diversify trees. grazing management Source: This study. Intensive vegetable production. biochar Grassland–to-plantation. annual-to-perennial grass. Figure 5. rotation diversification. annual-to-perennial grass. improved pastures Biochar. intensify rotation. biofertilizer application.7 million). intercropping. residues. biochar Latin America Diversify trees. no-tillage. cropland–to–grassland Inorganic fertilizer. crop-to-plantation.to-plantation. manure. improved irrigation. grazing management. rainwater harvesting. increased resilience. include trees. improved irrigation Residues. GHGs from poor land management will continue to accumulate in the atmosphere. terracing. no-tillage. biochar. annual-to-perennial grass. cross-slope barriers.8 billion). inorganic fertilizer. the growing of crops near existing trees. rainwater harvesting. the land management practices with the largest costs are mainly those associated with trees. rotation. provides synergy between profitability and increased soil carbon sequestration. biofertilizer.1 million).7 billion).0 Gt CO2-eq for Asia (table 5. pasture-to-forest.2). and organic soil restoration also display relatively high costs in Asia. intensive vegetables. intensify rotation. inorganic fertilizer. include trees. pasture to plantation. Private benefits that motivate decisions often fall short of social costs. slope barriers.53 C H A P T E R 5 — E C O NOMICS OF SOIL CARBON SE QUESTR ATION TABLE 5.2 indicates that all the land management practices generate benefits to the farmers. residues. cover crops. cover crops. organic soil restoration. rotation intensification. diversify rotation. For instance. afforestation. intercropping. and rotation diversification in Latin America (US$30. manure. cover crops. alley farming Asia Intensify rotation. cover crops. afforestation. rainwater harvesting. inorganic fertilizer in Asia (US$154. other soil amendments. improved fallows. crop-to–grassland Include trees. as afforestation tends to take land out of production for a significant period of time. but at varying costs to the public. cropsto-plantation. with the implication that in the absence of countervailing policies. improved irrigation.1: Private Savings of Different Technologies Per Ton of Carbon Dioxide Sequestered LESS THAN US$50 US$51 TO $100 MORE THAN US$100 Africa Cover crops. cover crops. 5.2: Public Costs of Different Technologies Per Ton of Carbon Dioxide Sequestered LESS THAN US$10 US$10 TO $20 MORE THAN US$20 Africa Tree crop farming. grazing management Improved irrigation. residues. rainwater harvesting. and Latin America (US$5. grazing management. pasture establishment on degraded land Asia Residues. include trees Source: This study. intercropping. alley farming. and reduced GHG emissions. residues.

Forest. Synergies and trade-offs in CSA affect decision making at various levels ranging from the household to the policy levels. Figure 5.3 reveals synergies between profitability and mitigation in two agroforestry systems: intercropping and alley farming (top right quadrant of figure 5.3). Intercropping is CARBON SEQUESTRATION IN AGRICULTURAL SOILS . as the graphs for other regions exhibit similar patterns leading to the same conclusions. Notes: The public costs for Africa were adapted from a World Bank study on Nigeria’s Agricultural. Billion) for the B1 Scenario Latin America Source: This study.54 C H A PTER 5 — EC ONOMIC S OF SOIL CA R B ON SEQU ES TR ATION other soil amendments improved fallow afforestation include trees slope barriers terracing residues rotation diversification rotation intensification cover crops manure alley frming intercropping inorgnic fertilizer no tillage rainwater harvesting intensive vegetables afforestation crop-to-plantation cover crops intensify rotation improved irrigation biofertilizer organic soil restoration include-trees biochar manure no tillage alley frming inorgnic fertilizer rainwater harvesting residue include-trees manure intercropping pasture to plantation afforestation cover crops pasture to forest diversify trees grassland to plantation rainwater harvesting intensify rotation biochar diversify rotation Asia improved irrigation 20 0 –20 –40 –60 –80 –100 –120 –140 –160 residues 50 0 –50 –100 –150 –200 –250 –300 –350 –400 Africa no tillage 4 2 0 –2 –4 –6 –8 –10 –12 –14 –16 tree crop farming FIGURE 5. trade-off was analyzed by using two-dimensional graphs to depict relationships between carbon and profitability and between private benefits and public costs. The analysis was limited to the Africa dataset.2: Total Private Benefits (Blue) and Public Costs (Red) of Land Management Practices (US$. The public costs for Asia and Latin America were assumed to increase proportionately to the state support for agriculture for China (8 percent) and Brazil (6 percent). and Other Land Use sectors where public support for agriculture is 3 percent. respectively. Synergies and trade-offs analyses can therefore help in quantifying the extent of “triple wins” of different land management technologies. In this study.

259. A2 = a world more divided and independently operating self-reliant nations.8 A2 3. A1b = a world more integrated with a balanced emphasis on all energy sources.7 B2 3.3: Technical Mitigation Potential. BILLION ) Africa B1 3.55 C H A P T E R 5 — E C O NOMICS OF SOIL CARBON SE QUESTR ATION TABLE 5.224.4 42.4 B1 2.8 A1b 2.6 A1b 3.9 B2 2.3 A2 3.6 19.4 55.8 40.368. B2 = a world more divided but more ecologically friendly.448 105.678 111.321 273.8 150.310.097 319.1 Asia Latin America Source: This study.7 A2 6.678 1.3 143.5 131.388 1. Notes: B1 = a world more integrated and more ecologically friendly.3: Trade-Offs Between Profitability and Carbon Sequestration of Sustainable Land Management Technologies in Africa profit per tone of carbon dioxide sequestered (US $) 1000 No-tillage Inorganic fertilizer Intercropping 100 Alley farming Manure Cover crops Soil amendments Crop residues Include trees Terracing 10 Rotation intensification Rotation diversification Afforestation Tree crop farming Rainwater harvesting Improved fallow Cross slope barriers 1 0 2 4 6 8 carbon dioxide sequestered (ton per hectare per year) Source: This study.8 44. and Public Costs of the Land Management Technologies by 2030 TECHNICAL POTENTIAL (MILLION TONS CO2-eq) SCENARIO PRIVATE BENEFITS (US$.505 108.6 B2 7.977 1.425 279.3 B1 5.4 19.007 1. EC O N O M I C A N D S E CT OR WORK 10 .926 120. Private Benefits.3 A1b 6. FIGURE 5.4 20. BILLION ) PUBLIC COSTS (US$.9 22.1 159.538 288.

and adaptation benefits in agriculture. The low profits suggest that farmers may be reluctant to privately invest in these technologies.4: Relationship between Private Benefits and Public Costs in Africa private benefit (per tonne of carbon dioxide sequestered) 1. Strong public FIGURE 5. Manure also has quite low nutrient content relative to inorganic fertilizers. 104 kg/ha in South Asia.3 have high carbon sequestration rates but are modestly profitable. Public cost refers to government support toward the implementation of land management practices. Yields also increase with manure application and accumulation of soil carbon. mitigation. The time-averaged. the biomass of crop residues does not accumulate easily. and are more sustainable in the long run. but with patterns that depend on crop type. The relationship between public costs and private benefits of the land management technologies is shown in figure 5. Judicious fertilizer application counters soil nutrient depletion.3). reduces deforestation and expansion of cultivation to marginal areas. benefit more farmers.3 is relatively small compared to that of agroforestry systems. so a large amount needs to be applied on relatively small fields. preferably leguminous trees or shrubs. Both are important strategies for increased productivity and resilience of the farming system. Manure plays a crucial role in improving fertilizer use efficiency and soil moisture conservation Manure is less profitable than inorganic fertilizer because of the labor costs associated with collecting and processing manure (top left quadrant of figure 5. Technologies that involve significant change in land-use (afforestation and improved fallows) and landscape alteration (terracing and cross-slope barriers) incur high public costs but generate low private benefits (lower right quadrant of figure 5. resulting in lower mitigation benefits. Also. investments in improved land management. and other administrative costs. input subsidies. It reduces the amount of land available for cultivation in the short run. and establishing barriers across sloping areas.000 No-tillage Inorganic fertilizer Intercropping 100 Alley farming Manure Cover crops Terracing Include trees Crop residues Crop rotation 10 Afforestation Tree crop farming Improved fallow Rainwater harvesting Cross slope barriers 1 0 3 5 8 10 13 public cost ($ per tonne of carbon dioxide sequestered) Source: This study. and increases crop yields. Reversing developing countries’ (especially Africa’s) soil productivity declines cannot be adequately addressed without increased fertilizer use. whereas alley farming is growing crops simultaneously in alleys of perennials.4. but can lead to overall increases in productivity and stability in the long run. Manure systems are also associated with high methane emissions. improved fallow involving the use of fast-growing trees to accelerate soil rehabilitation. tends to take land out of production for a significant period of time. Afforestation. extension services. CARBON SEQUESTRATION IN AGRICULTURAL SOILS . Land management technologies in the lower right quadrant of figure 5. Public support that focuses on research. The pattern of public support is as crucial as the amount of support for full realization of productivity. including trees in croplands.56 C H A PTER 5 — EC ONOMIC S OF SOIL CA R B ON SEQU ES TR ATION growing crops near existing trees. This explains why manure works well for smallscale intensive and high-value vegetable gardening. and land tenure rather than on input support are generally more effective.4). They include investments in seeds and seedlings. Farmers apply 9 kg/ha of fertilizer in Africa compared to 86 kg/ha in Latin America. and 142 kg/ha in Southeast Asia (Kelly 2006). above-ground biomass of crop residues and other technologies in the lower left quadrant of figure 5. The relatively high profitability of no-tillage derives primarily from the decrease in production costs after establishment of the system.

1: Terracing and Landscape Management in Bhutan Source: Curt Carnemark/World Bank. and loan guarantees (Agwe. and regional scales to ensure synergies are properly captured. and rainwater harvesting with lower profits and also manure and no tillage that generate relatively higher profits require minimal government support (lower left and upper left quadrants of figure 5. and livestock productivity was falling. difficult targeting. and the support helps improve targeting through market-smart subsidies while providing impetus for private sector input development. It entails the integrated planning of land. matching grants.3 IMPLICATIONS OF THE TRADE-OFFS IN LAND-USE DECISIONS The trade-offs exhibited by the land management technologies have important implications for land-use decision making. the subsidies help achieve social rather than economic objectives. and sectors.4) reflects the use of subsidies in spurring farmers’ access to the technology. environment. 5. and crowding out of commercial sales. forests. To address these challenges. It allows trade-offs to be explicitly quantified and addressed through negotiated solutions among various stakeholders. fresh water cycling. Morris. watershed. Fertilizer subsidy is. and pollination. and water at local. time. however. The landscape level is the scale at which many ecosystem processes operate and at which interactions among agriculture. After several years of intensive grazing in Costa Rica and Nicaragua. Sustainable land management interventions should be planned and implemented in a coordinated manner across space. Thus. Crop residues. biodiversity protection. The relatively high public cost of inorganic fertilizer (top right quadrant. agriculture. crop rotation. figure 5. respectively). fisheries. The first example is the silvopastoral farming systems of Costa Rica and Nicaragua. carbon storage. erosion was accelerating. fertilizer subsidies are appropriate in situations when the economic benefits exceed costs. The landscape approach provides a framework for the better management of ecosystem services. These technologies generally have low mitigation potentials. Examples of market-smart subsidies include demonstration packs. a pilot project introduced silvopastoral techniques PHOTO 5. vouchers. associated with high fiscal costs. Working at the landscape level with an ecosystems approach is useful for addressing food security and rural livelihood issues and in responding to the impacts of climate change and contributing to its mitigation. pastures were degraded. and development objectives are mediated. Two examples taken from World Bank (2011c) illustrate the efficacy of the landscape approach.4.57 C H A P T E R 5 — E C O NOMICS OF SOIL CARBON SE QUESTR ATION involvement in these technologies is justifiable given their relatively high mitigation potentials. and Fernandes 2007). EC O N O M I C A N D S E CT OR WORK . cover crops. such as agricultural productivity.

leakage. and trees dispersed in pastures.and supply-side interventions for facilitating the adoption of sustainable land management inputs. Silvopastoral techniques were used to transform degraded lands with monocultures of one grass species into more complex agroforestry systems of different tree species. and 60 percent in farm income. most of the land management technologies require significant up-front expenditure that poor farmers cannot afford. The absence of collective action will hinder successful uptake.000 ha between 2001 and 2007.5 POLICY OPTIONS FOR SOIL CARBON SEQUESTRATION Private benefits that drive land-use decisions often fall short of social costs. when technologies are inconsistent with community rules and traditional practices. As a result.5 summarizes possible demand. Beyond these. improved availability of inputs is a necessary but insufficient condition for adoption of land management practices. The methane emission per product kilogram decreased. improving the livelihoods of 2. south-south knowledge exchange. trees. while biodiversity (measured by the number of bird species and water quality) increased. and reduce methane emissions. Last.58 C H A PTER 5 — EC ONOMIC S OF SOIL CA R B ON SEQU ES TR ATION to 265 farms on 12. scientific research.4 suggests that lack of credit and inputs and land tenure problems are by far the most important factors for adoption across the range of technologies. there are a number of other implementation constraints. Second. However. carbon sequestration may not reach an CARBON SEQUESTRATION IN AGRICULTURAL SOILS . Table 5. thus. but also significantly lowered their variability. 38 percent in stocking rate. Third. lack of information on the potentials of alternative techniques of farming and limited capacity is a major constraint in many developing countries. sequester carbon. residue management. the nonavailability of inputs in the local markets can be a significant barrier in situations where farmers might want to invest in a technique. diffusion. Replanting and a grazing restriction allowed the perennial vegetation cover to increase from 17 to 34 percent between 1999 and 2004. 5. Revegetation has successfully restored the devastated Loess Plateau to sustainable agricultural production. It is estimated that as many as 20 million people have benefited from the replication of the Loess Plateau approach throughout China. Learning hubs. For instance.4 SUSTAINABLE LAND MANAGEMENT ADOPTION BARRIERS Despite the fact that improved land management technologies generate private benefits. Factors affecting adoption tend to be more specific to the land management technologies.and supply-side measures will allow the demand and supply to grow. willingness and the ability to work together are crucial for many technologies such as improved irrigation and communal pastures. live fences. The last example is one of the world’s largest erosion control programs in China. the farming system involving no-tillage. Results showed a typical win-win situation: An annual sequestration of 1. the evolution of farm and family incomes has shown a steady increase. Careful selection of combinations of demand. 5. and shrubs on previously cultivated sloping lands. riparian forests. is highly knowledge intensive. and technical support mechanisms may increase innovation and facilitate adoption of improved land management technologies. their adoption faces many socioeconomic and institutional barriers. leading to the emergence of viable private sector–led input markets. The knowledge base of land management practices at the local level can also be improved through careful targeting of capacity development programs. and impact of these land management technologies. Secure land rights is a precondition for climate-smart agriculture as it provides incentive for local communities to manage land more sustainably. regional platforms. Better market prices for crops and other agricultural produce are crucial. sustaining soil fertility and enhancing carbon sequestration. Behavioral change through education is required to enable changeover to improved land management technologies. Agricultural production has changed from generating a narrow range of food and low-value grain commodities to high-value products. their adoption will most likely encounter the resistance of the people. conservation agriculture. requiring training and practical experience of those promoting its adoption. and additionality (box 5. Together with terracing. It is unlikely that any of these interventions alone will be effective in increasing input use. A payment scheme for environmental services—carbon sequestration and biodiversity conservation—was introduced as an additional income stream for livestock production.1). Ill-defined land ownership may inhibit sustainable land management changes.5 million people and securing food supplies in an area where food was sometimes scarce in the past. First. The project encouraged natural regeneration of grasslands. and use of cover crops.5 Mt of CO2-equivalent was accompanied with increases of 22 percent in milk production. these measures not only increased average yields. Table 5. The commonly cited risk-related barriers to adoption of carbon sequestering technologies in agriculture are permanence. The techniques have been shown to enhance biodiversity. Fourth.

Permanence: Permanence refers to the secure retention of newly sequestered carbon. and less emission generated by the project (Fynn et al. ex ante discounting. book balancing at the end of the project is also possible Relatively easy to impose discounts on credits if amounts of reversal can be reasonably projected Boosts attractiveness of investment by allowing credits to be earned as soon as they are generated by the project. and reduction in nitrous oxide and methane emissions are nonsaturating.59 C H A P T E R 5 — E C O NOMICS OF SOIL CARBON SE QUESTR ATION BOX 5. control of grazing in an area might force herders to move their animals to another location. Note that not all agricultural mitigation options are transient. Carbon sequestration only removes carbon from the atmosphere until the maximum capacity of the ecosystem is reached. For instance. Permanence. which may be about 25 years for most land management practices. monitoring. 2007). and additionality can be addressed through temporary crediting. emissions reduction must be in addition to what would have occurred under the business-as-usual scenario. perpetual accounting may hinder balancing the books at the end of a finite-life project Transaction costs Measurement. not observed changes in carbon MMV are carried out into perpetuity Source: Table synthesized from Murray et al. These can be based on stock change or average stock change during the period Environmental rigor Rigorous as temporary credits must be replaced when they expire Credits may not equal debits for a given project. Substitution of fossil fuels by bioenergy is a permanent mitigation option. however. credits are reduced by formula. as such. optimal level from a social point of view unless some mechanisms exist to encourage farmers. ex ante discounting may lead to underdebiting or overdebiting of ex post reversal.1: Risk-Related Barriers to Adoption of Soil Carbon Sequestration Activities • • of leakage. Macroeconomic policies induce changes in market conditions and prices. rather. Countries must be prepared to access new and additional finance. This could be as a result of technology transfer or changes in market conditions that stimulate mitigation activities. 2010). TEMPORARY CREDITING EX ANTE DISCOUNTING COMPREHENSIVE ACCOUNTING Description Balances debits and credits for finite periods with provision for reversal Accounts for the possibility of future loss by reducing the amount of credit at the onset based on the expectation of reversal Balances debits and credits as they occur in the course of the project. Strengthen the capacity of governments to implement climate-smart agriculture. Additionality is usually calculated as postproject carbon stocks less the forward-looking baseline. Some public policies that can potentially incentivize carbon sequestration include the following: EC O N O M I C A N D S E CT OR WORK 1. and verification (MMV) and contract renewal costs need to be borne by the project MMV are not necessary. and comprehensive accounting (Murray et al. • Leakage: Leakage occurs when a project displaces greenhouse gas emissions outside its boundary. There is a need to build the technical and institutional . Storage of carbon in soils is relatively volatile and subject to re-emission into the atmosphere in a subsequent change in land management. The risk of nonpermanence is lower when the adoption of soil carbon sequestration practices also leads to more profitable farming systems. less deduction for leakage and risk of reversal. 2007. positive leakage spillover effects that lead to reduction in emissions outside the project boundary can occur. While most occurrence of leakage has a negative effect on project benefits. which in turn influence farmers’ land-use and management practices. This achieves consistency as long as the system is monitored perpetually Feasibility of implementation Enables up-front payment. leakage. Economic adjustment to meet market demand is the underlying driver Additionality: The concept implies that in order to attract compensation.

*** = High importance. ** = Moderate importance. 2011. weather-indexed crop insurance Strengthen business finance and risk management Use credit guarantee and innovative insurance schemes Improved quality and dissemination of market information Public and private sector information systems easily accessible to farmers Improve supply chain coordination mechanisms Product grades and standards Market information systems to reduce information costs Protecting farmers against low and volatile output prices Investment in measures to reduce production variability such as drought-tolerant crops. Global cooperative agreement. and storage systems Empowering farmers by supporting producer organizations Investment in rural education Training farmers in organizational management Improving the resource base so that input use is more profitable Investment in soil and water management and irrigation infrastructure Source: Modified from Agwe.60 C H A PTER 5 — EC ONOMIC S OF SOIL CA R B ON SEQU ES TR ATION TABLE 5. TABLE 5. and Fernandes (2007). Although the negative impacts of agricultural production in terms of land-use change and GHG emissions were reasonably well covered by the convention.4: Relative Importance of Different Factors for Adopting Improved Land Management Practices LAND MANAGEMENT TECHNOLOGY INPUTS/ CREDITS MARKET ACCESS TRAINING/ EDUCATION LAND TENURE RESEARCH INFRASTRUCTURE Inorganic fertilizer *** ** ** ** * ** Manure ** ** * ** * ** Conservation agriculture ** ** *** ** ** * Rainwater harvesting ** ** ** *** ** ** Cross-slope barriers ** * ** ** ** * Improved fallows ** * * *** ** * Grazing management *** *** ** *** ** * Source: Synthesized from Liniger et al.. Redressing this omission promises to foster a more balanced perspective in which food security is not necessarily at odds with climate change adaptation CARBON SEQUESTRATION IN AGRICULTURAL SOILS .5: Interventions for Facilitating Increased Input Use DEMAND-SIDE INTERVENTIONS SUPPLY-SIDE INTERVENTIONS Strengthen soil-crop research and extension Support to public agencies Public-private partnership On-farm trials and demonstrations Reduce input sourcing costs Lowering trade barriers to increase national and regional market size Improve farmers’ ability to purchase inputs Improve access to credits Phased and incremental use (e.g. Morris. 2. capacity of government ministries to implement climate-smart agriculture programs. Existing national policies. Key * = Low importance. Given the tremendous significance that agriculture has for the global climate. strategies. irrigation. deep-rooted crops. Readiness for carbon sequestration and climate-smart agriculture can be achieved through improved extension services and training in relevant land management technologies for different locales. and investment plans should be strengthened to form the basis for scaling-up investments for climate-smart agriculture. small bags for fertilizers) Implement laws that enables farmers to use risk-free collaterals for loans Reduce distribution costs Improve road and rail infrastructure to lower transport costs Provide farmers with risk management tools Improved weather forecasting. progress in incorporating it into the UNFCCC has been slower than many people hoped for. the real and potential contributions the sector can and does make in terms of sequestering carbon in agricultural biomass and soils were for the most part omitted.

and significant up-front costs. finite public resources can be more selectively targeted using the criteria given above—prioritizing technologies that generate no short-term returns and those that most effectively address the barriers that prevent prospective adopters from moving forward. Sustainable Land Management in Practice—Guidelines and Best Practices for Sub-Saharan Africa.. and development finance will be required to scale-up improved land management practices.. For technologies such as conservation agriculture that require specific machinery inputs.. A more practical and thorough picture makes it possible for agriculture to be rewarded for its positive environmental impacts. Washington. J.. DC. Factors Affecting Demand for Fertilizer in SubSaharan Africa. Liniger. B. Public investment can also be used to leverage private investment in areas such as research and development. 2011.. and to be an integral part of “the solution” as well as part of “the problem. South Africa. and Gurtner. 3. C. “Economic Consequences of Consideration of Permanence. While this may appear a tall order in countries with severe budget constraints. Kelly. A. 2006. 2007. Murray.. Rangelands: Issues Paper for Protocol Development. R. New York. Integrating sources of climate finance with those that support food security may be one of the most promising ways to deliver climate-smart agriculture with the resources it requires. V. and Additionality for Soil Carbon Sequestration Projects.. L. particularly when government priorities translate clearly into business opportunities and certain areas of investment are looked upon favorably by public officials and institutions. Climate-Smart Agriculture—A Call to Action.. the parties asked the UNFCCC Subsidiary Body for Scientific and Technological Advice to explore the possibility of a formal work program on agriculture. Leakage. and Fernandes. Particular attention should go to encouraging private financial service providers to tailor instruments that enable farmers who adopt SLM practices to overcome the barriers described above. T. Oldfield. R. At the 17th Conference of Parties to the UNFCCC in Durban. Nationally owned climate-smart EC O N O M I C A N D S E CT OR WORK agricultural policies and action frameworks will increase the adoption of sustainable land management practices. P. Schohr. C. A. Neely. such as indexbased weather insurance or weather derivatives. World Bank. 2007. are areas of private investment that can be encouraged through public policy and public-private partnerships. P. A blend of public. Kustin. In some cases. REFERENCES Agwe. M. Bundling agricultural credit and insurance together and providing different forms of risk management.. P. Environmental Defense Fund. Raise the level of national investment in agriculture. grant funding or loans may be more suitable to overcoming adoption barriers. There is also the potential for carbon finance to support farmers during the initial period before the trees in agroforestry systems generate an economic return. E. Brown. and Wong. J. 2011. Agriculture and Rural Development Discussion Paper 23.” Climatic Change 80: 127–143. Introducing policies and incentives that provide an enabling environment for private sector investment can increase overall investment.S.” This is vitally important because agriculture needs to be fully incorporated into adaptation and mitigation strategies. However. C. A. World Overview of Conservation Approaches and Technologies and Food and Agriculture Organization of the United Nations. Fynn. M. George. and Ross. H. Boost financial support for early action. Washington. and in developing improved seeds and seedlings. 2010. involving the private sector in climatesmart agriculture and sustainable land management is the other. payment for ecosystem services scheme could be used to support farmers and break the adoption barrier. . 5. For technologies that generate significant private returns. Mekdaschi Studer.. Hauert. 4. J. C. As a result. Laca.. Create enabling environments for private sector participation.. C. L. T. Soil Carbon Sequestration in U. 2011. “Africa’s Growing Soil Fertility Crisis: What Role for Fertilizer?” World Bank Agriculture and Rural Development Note Issue 21 (May): 4 pp. Alvarez. E. World Bank. establishing tree plantations. T. private.61 C H A P T E R 5 — E C O NOMICS OF SOIL CARBON SE QUESTR ATION and mitigation (an unworkable conflict in which longer term environmental concerns are virtually guaranteed to universally lose out politically to the more immediate concern of food supply). DC. R.. the international community has recognized the importance of integrating agriculture into the ongoing negotiations on the international climate change regime.. M.. J. Sohngen.. in November. relatively affordable technologies that generate quick and demonstrable benefits may warrant priority and potentially establish some of the channels through which more sophisticated technologies are dispersed in the future. M. public investment is only one sphere. Morris. This private investment can be targeted to some degree as well. B.

.

2 18. A ND FEATUR E IN LA ND MA NA GEMENT Appendix A: FARMING PRACTICE EFFECT.63 AP P E N D I X A — FA RMING P RACT ICE E F F E CT.5 12 100 6 24 Agroforestry Trees/forest 125 Intercropping 14 Alley farming 46 Tree-crop farming 44 Land-use changes Afforestation 16 Grazing pasture 32 Cropping intensity 55 Soil management Crop rotation 49 Improved fallow 71 Natural fallow 68 Water management Water/rain harvesting 33 Slope/barriers 22 Terracing 15 44 Others 100 Biochar 11 11 1. AND FEATURE IN LAND MANAGEMENT PRACTICES Africa LAND MANAGEMENT PRACTICES NUMBER OF ESTIMATES Nutrient management Chemical fertilizer 30 Animal manure 30 Tillage and residue management No tillage 108 Residues 46 Mulches Cover crops SUBTOTALS MEAN DURATION MEAN DEPTH EXPERIMENTAL DESIGN (%) 60 8.3 15 100 184 4 15 100 185 6 22 100 2. NUMBER OF ESTIMATES. NUMB ER OF ESTIMATES .4 10 .4 103 3 20 100 187 4.5 10 100 56 2.8 EC O N O M I C A N D S E CT OR WORK 7.8 Soil amendment 15 15 1.

3 20 99 75 8.5 29 5 25 8. NUMB ER OF ESTIMATES .4 49 34 292 18.3 27 64 150 14.5 29 68 6 Bio-inoculant 3 Gypsum 8 Sulfur 5 Lime 2 Zinc 1 TOTAL EXPERIMENTAL DESIGN (%) 60 Crop-to-plantation Biochar MEAN DEPTH (cm) 4 Land-use change Crop-to-forest MEAN DURATION (yr) 48 Return of crop residues to field Rain harvest SUBTOTALS CARBON SEQUESTRATION IN AGRICULTURAL SOILS .0 26 97 328 9.64 AP P E NDIX A — FARMING P RACT ICE EFFECT. A ND FEATUR E IN LA ND MA NA GEM ENT Asia PRACTICES NUMBER OF ESTIMATES Nutrient management Application of fertilizer 297 Application of manure 146 Tillage and residue management Reduced or no till 189 Application of mulches 53 Cover crops 38 Agroforestry Inclusion of trees 58 Intercropping 17 Intensification Intensive vegetables 57 Annual-to-perennial 36 Intensify rotation 43 Improved irrigation 10 158 Crop-to-grassland 35 Reduced grazing 39 Other amendments and practices 443 17.6 18 100 14.

5 33.1 24.9 21.2 29. EC O N O M I C A N D S E CT OR WORK .65 AP P E N D I X A — FA RMING P RACT ICE E F F E CT.2 92 364 8.0 64 257 19. A ND FEATUR E IN LA ND MA NA GEMENT Latin America PRACTICES NUMBER OF ESTIMATES Nutrient management Application of fertilizer 74 Application of manure 25 Tillage and residue management Reduce or no till 56 Application of mulches 16 Cover crops 33 Graze residues 10 Agroforestry 6 Intercropping 7 Intensification Intensify rotation 25 Diversify rotation 43 Improved irrigation 34 Improved pasture 15 Improved fallow 8 Pasture-to-forest 62 Crop-to-forest 59 Pasture-to-plantation 53 Grassland-to-plantation 32 Crop-to-plantation 14 Reduced or excluded grazing EXPERIMENTAL DESIGN (%) 99 9.7 17.1 82 931 12.6 28.5 61 13 Land-use change Crop-to-pasture MEAN DEPTH (cm) 43 Diversify trees Annual-to-perennial MEAN DURATION (yr) 249 Return of crop residues to field Inclusion of trees SUBTOTALS 7 30 Other amendments Biochar 8 Lime 9 TOTAL Source: This study.5 5 17 5.0 38.3 61 138 15. NUMB ER OF ESTIMATES .8 90 56 8.

.

and humid ecosystems. the 50th percentile. Further. Manure Management For each stratum. it served as a proxy to consider increase of yields over time due to improved management practices including the increase in application of inorganic fertilizer (integrated nutrient management). ƒ initial carbon mass of humified organic matter (HUM). assuming a conventional management of 15 percent of residues left on the ground after harvesting. 7. respectively. one low organic input baseline scenario was modeled for each crop and crop area. manure management can be classified into direct manure application and application of composted manure. respectively. a farmer in a specific stratum whose current maize yield is within the 25th percentile may be able to increase the yields to within the 75th percentile due to increased inorganic fertilizer application. per ha per year for semi-arid. EC O N O M I C A N D S E CT OR WORK Generally. the inputs were in line with observations made by Young (1997).2 GLOBAL MITIGATION SCENARIOS Residue and Integrated Nutrient Management This scenario implies additional residue inputs due to crop management improvement. and 14 t d. and ƒ initial carbon mass of soil. pigs.AP P E N D I X B — G E NE RAL SCE NARIO ASSUMP T IONS A ND A PPLICATION FOR WORLD REGIONS Appendix B: B. sheep. The global data estimated manure application in kg per ha of nitrogen. the C input per ha for each kg N was calculated based on Food and Agriculture Organization of the United Nations (FAOSTAT) numbers of cattle. For instance. All models were run to equilibrium state increasing the organic inputs in 0.1 t C steps until the initial carbon stock represented the equilibrium of the specific soil in each stratum. ƒ initial carbon mass of slow decomposing biomass (BIO-S).1 GENERAL SCENARIO ASSUMPTIONS AND APPLICATION FOR WORLD REGIONS BASELINE SCENARIO Using the initial soil carbon stocks (in t C/ha) from the Harmonized World Soil Database. subhumid. and poultry for each region. The crop yields for each stratum are presented in Appendix C. Similar to the procedure for residue calculation.5. However. who estimated plant biomass requirements to maintain soil organic matter range between 3. the raw manure and composted manure model inputs in tC/ha were estimated by applying IPCC factors to the average amount of farm animals per ha (IPCC 2006). Therefore.m. ƒ initial carbon mass of resistant plant material (RPM). Two scenarios were considered with regard to increased productivity as a result of integrated nutrient management practices: A shift from low productivity to medium productivity (25 percentile to 50 percentile of crop yields in a specific stratum) and a shift from medium to high productivity (50 percentile to 75 percentile of crop yields in a specific stratum). ƒ initial carbon mass of fast decomposing biomass (BIO-F). goats. B. The calculation of residues inputs from the crops was based on the global crop yield data. the models were run in reverse mode to estimate ƒ initial carbon mass of decomposable plant material (DPM). 67 . Crop yields were grouped into three bins representing the 25th percentile. The average fresh yield was converted to amount of residues produced on the basis of IPCC equations (IPCC 2006). The required addition of organic inputs to the soil varied greatly depending on climate parameters and the clay content of the soil. and the 75th percentile of the yields of a specific crop in one stratum to assess the opportunity of adapting the residue management to local situations.

On average. Based on this average conversion. Like Africa. Agroforestry and Improved Fallow Agroforestry.43 C ha−1 was allocated as aboveground input and 1. 2005b. manure management (direct and composting). Rice is grown in the wet season under dry land farming. the use of several varieties of mucuna (Mucuna pruriens) in rotation with maize produced on average 6. ƒ In Mexico. was considered a mitigation potential for all climate regions. and agroforestry were modeled for each cluster. sustainable practices such as cover cropping. non-N-fixing forage. Compared to green manure/cover crops. and Gordon 2005a./ha (Yaqub et al. agroforestry. In addition. Gama-Rodrigues and Antonio 2011). These values represent the organic input from trees to the soil. either as litter or through pruning and mulching. In general. 50 percent residue retention was assumed. the average manure/composted manure production was calculated for its use in the RothC model. The above-ground biomass was converted into t C ha−1 yr−1 using the IPCC equations for N-fixing forage.01 C ha−1 as below-ground input.68 AP P E NDIX B — GENERA L SC ENA RIO A SS UMPTIONS A ND A PPLIC ATION FOR WORLD R EGIONS The amount of manure/composted manure represents the amount of potential manure production and not the amount of manure actually spread on the field in the baseline. manure management (direct and composting). the most dominant farming system is intensive wetland rice cultivation with or without irrigation. the input value for the model was 1. In the dry season. water harvesting.8 t d.3 APPLICATION TO WORLD REGIONS Africa In Africa. mixed smallholder farming systems are dominant (soybean. wheat. In addition./ha (Eilittä et al. and the remaining 50 percent was assumed to be removed as animal feed. Therefore. All mapping units (see page 45) in Africa were considered for the modeling. maize. such crops yield around 4 t dry matter ha−1 yr−1. fertilizer application. Improved manure and composted manure application are considered mitigation opportunities for all climatic regions. a second crop of rice (where irrigated) or another less water–demanding crop (legumes and coarse grains) is grown. and roots and tubers) with currently low input (organic and inorganic). Apart from rice. apart from Southeast Asian countries. and grass. Take for instance. there exists a significant trade-off between residues on the field versus residues used for livestock feeding. A residue management scenario of 50 percent of available residues per ha was modeled for each of the main crops in Asia. trees on cropland. the following: ƒ In Zambia.5 t d. improved fallows in maize systems with several nitrogen-fixing tree species (both coppiced and noncoppiced) resulted in above-ground carbon inputs of 2. CARBON SEQUESTRATION IN AGRICULTURAL SOILS .44 t C ha−1. crop yields have remained stagnant for decades due to continuous depletion of soil organic matter over time from unsustainable practices. 2010). the input value for the RothC model concerning improved fallow is found to be similar to that of other agroforestry systems.m. Agroforestry options that produce high-value crops and additional sources of farm revenues offer additional mitigation benefits. respectively. a robust average input value was used based on input values from various studies for tropical and temperate climate regions. of which 0. Voroney. green manuring. covering a wide range of different agroforestry practices such as alley cropping. There is a significant trade-off between residues on the field versus residues used for livestock feeding. the introduction of the mungbean (Vigna radiata) as a grain legume in the short fallow of the wheat-rice system produced a total biomass of 4. and residue management. Asia In many areas. including improved fallow.3 tC/ha and 1. increase yields. A residue management scenario of 50 percent of available residues per ha was modeled for each of the main crops in Africa. and so forth (Oelbermann.m. and enhance resilience to climate change need to be adopted. and water and nutrient management to improve soil carbon sequestration. 2003). the best package of practices for soil carbon sequestration for the region consists of a combination of manure application. ƒ In Asia. Based on the literature research. To reverse this situation. the input value for tropical and temperate agroforestry systems averaged 2.06 tC/ha. and then computing the average value for RothC modeling. green manuring. Green Manure/Cover Crops Green manure is a type of cover crop grown to add organic matter and nutrients to the soil.8 tC/ha on average (Kaonga and Coleman 2008). and agroforestry were modeled for each of the strata. Based on this. B. All mapping units in Asia were considered for the modeling. For each stratum.

and sorghum. Cover crop was modeled and applied to the total area of crops for which green manuring is practiced. and agroforestry (table B. EC O N O M I C A N D S E CT OR WORK Cover crop Cover crop Residue management AGROFORESTRY . The agricultural systems found in the mapping units/stratum are displayed in Table B. wheat. Green manure using winter cover crops during the fallow period was also modeled. and pulses. Central America Oceania The most dominant agricultural systems in Central America are sorghum. No-tillage in soybean/ maize systems was modeled and applied to the area where soybeans and maize are grown. soybean. and pulses cultivated as winter crops and usually in rotations. North America The dominant crops in mapping unit 1 are barley. but there are still opportunities to increase its use.2: Agricultural Systems and Mitigation Scenario in Central America MAPPING UNIT/ STRATUM SORGHUM BEANS MAIZE RICE 2 4 6 9 10 12 Mitigation options Source: This study. The main crops are wheat. rice. no-tillage has been adopted by many producers.69 AP P E N D I X B — G E NE RAL SCE NARIO ASSUMP T IONS A ND A PPLICATION FOR WORLD REGIONS TABLE B. maize. beans/maize. pulses. Crops are mostly cultivated during the summer with bare fallow during the winter. Compared to South America. Common land management practices in South America include rotational wheat/soybean and fallow systems. wheat. and tillage. No-tillage is used in TABLE B. Notillage was considered a mitigation option in 50 percent of the cropped area. soybean. and maize predominate. Residue management in rice systems was modeled. wheat.1. soybean. No-tillage was identified as another mitigation option. barley. Those in zone 3 are barley.1: Agricultural Systems and Mitigation Scenario in South America MAPPING UNIT/ STRATUM WHEAT SOYBEAN MAIZE SOYBEAN MAIZE BEANS MAIZE Cover crop Cover crop no-tillage Cover crop RICE AGROFORESTRY 2 4 6 8 9 12 Mitigation options Cover crop residue management Source: This study.2). South America Several agricultural systems exist in South America. In recent years. maize. The use of a cover crop during the fallow period was identified as a promising mitigation opportunity. cover crops and residue management of rice-based systems were identified as mitigation options. maize and soybean systems with residue management. In zone 7.

No-tillage was modeled with the average value for organic inputs for the two main crops used. different fractions of residues applied in the field were modeled (25 percent.70 AP P E NDIX B — GENERA L SC ENA RIO A SS UMPTIONS A ND A PPLIC ATION FOR WORLD R EGIONS fied above.042 7 0. the average manure/composted manure production was calculated for its use in the RothC model (table B. COMPOSTED MANURE t C/hA/APPL.030 0.061 11 0.031 0. and 8. CARBON SEQUESTRATION IN AGRICULTURAL SOILS .035 0.136 12 0.096 0. and poultry for each country of each region. The scenarios modeled include use of no-tillage. the average value for summer and winter cover crops was used.070 5 0. For each climate zone.023 0.046 9 0. but if there was more than one cropping season. pigs..056 0. Europe The main crops are wheat and barley in winter and maize in summer. and 75 percent) left in the field. For each mapping unit. Each crop was modeled separately. maize 1s and maize 2s).057 10 0. approximately 50 percent of the cropped area.019 0. the raw manure and composted manure model inputs in t C/ha were estimated by applying IPCC factors to the average amount of farm animals per ha (IPCC 2006). Winter cover crops during the fallow period for green manure were also modeled. each season was modeled separately (e. B. and the 75th percentile of the yields of a specific crop in one stratum to assess the opportunity of adapting the residue management to local situations. and 75 percent).085 3 0.3). the 50th percentile.078 4 0. The average fresh yield (for instance maize) was converted to amount of residues using IPCC Guidelines. Russia The main crops are wheat and barley cultivated as summer crops with bare fallow during the rest of the year. manure management can be classified into direct manure application and application of composted manure. 50 percent.046 0. no-tillage was assumed to be suitable on 35 percent of the cropped area. the average value of inputs for the main crops was used.075 2 0. For mapping units 2. For each zone. Residues are sometimes burnt just before sowing. Similar to the procedure for residue calculation. Cover crops during the fallow period for green manure were also modeled.110 8 0. Crop yields were grouped into three bins representing the 25th percentile. To account for possible trade-offs between retention of residues in the field and residues needed as livestock feed. Direct manure and composted manure application were modeled in combination with different fractions of crop residues (25 percent.017 0. goats. The calculation of residues inputs from the crops was based on the crop yield data identi- Manure Management Generally.029 0.232 Source: This study.3: Manure C Inputs for the Agroecological Zones (AEZs) in Africa Based on FAOSTAT MAPPING UNIT/AEZ DIRECT MANURE t C/hA/APPL. Residue is commonly left on the field or incorporated (around 75 percent of the cropped area). 7. TABLE B. 50 percent. Cover crops and no-tillage techniques are rarely used (around 1 percent). Tillage is frequently used.025 0.g.4 DETAILED MODELING FOR AFRICA Residue and Integrated Nutrient Management This scenario implies additional residue inputs due to crop management improvement. 1 0.073 6 0. sheep.032 0. The C input per ha was calculated based on FAOSTAT numbers of cattle.

1: FAO Land-Use Map 10 Herbaceous-mod. The General Agroforestry Mitigation Scenario This scenario can be seen as representative for all agroforestry systems on cropland. intensive or higher with large scale irrigation 5 Forestry-pastoralism moderate or higher with scattered plantations 17 Agriculture-large scale irrigation (>25% pixel size) 6 Forestry-scattered plantations 18 Agriculture-protected areas 7 Herbaceous-no use/not managed (Natural) 19 Urban areas 8 Herbaceous-protected areas 20 Wetlands-no use/not managed (Natural) 9 Herbaceous-extensive pastoralism 21 Wetlands-protected areas Source: FAO and World Bank. The input values were calculated 71 . and Land Rehabilitation Five different agroforestry mitigation scenarios were considered in this study. Only the mean values of residues were used for the modeling.. The activity data are the crop areas of maize and sorghum. and groundnuts. ƒ Cowpea + maize and cowpea + sorghum: This scenario assumes that cowpeas are predominantly intercropped with maize and sorghum. pigeon peas. The input values are shown in table B. Green Manure/Cover Crops (GMCCS) Based on a study by Barahona (2004). ƒ Groundnuts + maize and groundnuts + sorghum: This scenario assumes that groundnuts are intercropped with maize and sorghum. intensive pastoralism FAO Land use system 11 Herbaceous-intensive pastoralism Undefined 13 Rainfed agriculture (subsistence/commercial) 1 Forestry-no use/not managed (Natural) 14 Agro-pastoralism mod. the largest share of GMCCs worldwide is from Africa (51 percent) with maize cropping systems being the most dominant (66 percent). The following GMCCs scenarios are considered for the modeling: ƒ Mucuna sp. The input values are the strataspecific combinations of crop residues of groundnuts in addition to the residues of maize and sorghum. (2006) and Anthofer (2005). Agroforestry. respectively. The most frequently used GMCCs are Mucuna sp. respectively. intensive 2 Forestry-protected areas 15 Agro-pastoralism intensive 4 Forestry-pastoralism moderate or higher 16 Agro-pastoralism mod. Other main crops include cassava and sorghum.4. Improved Fallow. The input values are the strata-specific combinations of crop residues of cowpeas in addition to the residues of maize and sorghum.AP P E N D I X B — G E NE RAL SCE NARIO ASSUMP T IONS A ND A PPLICATION FOR WORLD REGIONS FIGURE B. The activity data for this scenario are potentially the area of all crops.: An input value of 3.27 t C/ha/year was used for the modeling in all strata based on Kaizzi et al. The activity data were the crop areas of maize and sorghum. Only mean values of residues EC O N O M I C A N D S E CT OR WORK were used for the modeling. Cowpeas.

35 2.78 2.42 3.40 1.64 2. Clay 50 AEZ 02.25 3.55 1.73 2.78 1.14 1. N AEZ 07.69 2.28 3.72 2. S AEZ 10. Clay 50 AEZ 01.89 1.83 2.12 3.03 4.00 0.94 2. S AEZ 12.36 2.27 3.02 4.34 1.00 2. S AEZ 09. Clay 75.84 2.86 1.67 2.00 GROUNDNUTS + MAIZE (tC/ha/YEAR) 1. Clay 25 AEZ 12. N AEZ 09.92 3. Clay 75.51 1. S AEZ 09.00 1.00 1.94 1.27 3.73 1. Clay 25 AEZ 06.52 2. S AEZ 09.85 1.44 1.74 4. S AEZ 08.27 3.27 3.27 3.00 2.00 0.00 2.17 1. N AEZ 07.76 1.27 3.00 COWPEA + SORGHUM (tC/ha/YEAR) 1.00 1.42 2.27 3.27 3.81 2.62 2.62 2. S AEZ 08.00 0. Clay 25.61 1. Clay 25.27 3. Clay 50.97 3.00 1.57 0.73 1.99 1.72 AP P E NDIX B — GENERA L SC ENA RIO A SS UMPTIONS A ND A PPLIC ATION FOR WORLD R EGIONS TABLE B.76 1. Clay 75. Clay 25.80 2. Clay 25.88 0.12 0.66 0.81 2.77 1.27 3.27 3. Clay 50 AEZ 05.68 3.66 3.08 2. Clay 75 AEZ 02. Clay 75.27 3. Clay 50.78 4. Clay 50.27 3. Clay 25 AEZ 03.00 1.00 2.00 1.27 3.03 1. Clay 25.62 4.89 2. Clay 50 AEZ 06.95 1.66 1.44 2.99 2. Clay 75 AEZ 07.55 0. S AEZ 08.27 3.27 3.96 3. Clay 75.11 1. Clay 25.91 1.27 3.81 2.40 0.70 3. N AEZ 07.27 3. Clay 50.79 1.71 4.10 3.27 3. Clay 25. S AEZ 11.27 3.09 3.10 4.71 2.00 1.23 3. Clay 25 AEZ 02.00 2.85 5.27 3.08 0.27 3. Clay 25 AEZ 04.15 2.00 2.74 2.45 2.58 3.27 3. S AEZ 07.62 0.52 1. Clay 50 AEZ 03.61 2.00 1.93 2.27 3.90 0.27 3.27 COWPEA + MAIZE (tC/ha/YEAR) 1.00 2. N AEZ 11.24 1.35 1. Note: AEZ = Agroecological Zone.08 2. Clay 50.72 0. Clay 75 AEZ 03. Clay 25.61 1.43 1.78 1.00 1. Clay 75 AEZ 06.27 3. N AEZ 08.4: C Inputs for Different Green Manure/Cover Crop Systems MAPPING UNIT (AFRICA) MUCUNA (tC/ha/YEAR) AEZ 01.19 0.27 3.27 2.25 3.70 1. Clay 75 AEZ 05.19 0.76 0. Clay 25 AEZ 05.27 3.56 0.53 3. Clay 50 AEZ 12.87 2.26 2. N AEZ 10.27 3. Clay 75.55 0.88 3.27 3.27 3. Clay 50. Clay 25 AEZ 01.27 3. S AEZ 10.27 3.91 2.06 1. Clay 75.58 1.15 0.40 1.20 1.44 1.18 3.40 1.63 1.51 3.27 3. Clay 50.47 3.27 3.27 3.27 3.71 0.37 2.51 3.71 3.00 1.29 2.57 1.49 0.36 2.13 1.00 1.50 0.23 2.46 1.73 2. Clay 25.45 2. Clay 50 AEZ 04.27 3.62 1. Clay 75.06 2. S AEZ 11.71 2. N AEZ 09.04 2.94 2. S AEZ 11.27 3.57 1.81 3.83 0. Clay 75 3. Clay 50. CARBON SEQUESTRATION IN AGRICULTURAL SOILS .38 Source: This study.00 1.93 1.19 0.50 2.33 5.27 3. Clay 75.27 3.27 3.00 1. S AEZ 07. Clay 50.27 3.58 2.82 3.27 3.59 2. S AEZ 10. N AEZ 11.00 1.41 2.02 1.91 3. N AEZ 08.59 1.28 3. N AEZ 10. Clay 50.49 1.12 1.87 1.27 3.62 0. N AEZ 10.00 1.34 2.65 2.27 3.15 2.27 3.62 3.87 2.50 1.84 0. N AEZ 08.00 2.27 3.00 2.79 3.00 0. Clay 75.65 0.91 0.87 0.27 3.71 3.27 3.87 2.98 1. N AEZ 09. Clay 25. N AEZ 11.72 1.58 GROUNDNUTS + SORGHUM (tC/ha/YEAR) 2.88 2.58 1. Clay 75 AEZ 04.

81 3.62 COPPICED IMPROVED FALLOW + MAIZE (tC/ha/YEAR) 4.19 8.843 3.17 5.58 5. Clay 50 AEZ 01.90 4.843 3.19 8.843 3.17 5.17 5.843 3.17 5.55 6.35 3.46 3. Clay 50.53 4.96 4. N AEZ 11. N AEZ 07.843 3.40 3.54 4.12 LAND REHABILITATION (tC/ha/YEAR) 3.19 8.17 5. N AEZ 07.843 3.843 3.45 4.17 1.17 1.51 4.85 3.58 5.19 8.17 5.843 3.05 3.843 3. Clay 50 AEZ 05.19 8. Clay 25. Clay 50.17 5. Clay 50 AEZ 12.15 3.44 5.83 3.42 4.80 4.19 8.19 8.19 8.83 3.48 2.95 3.19 8.843 3. Clay 25. Clay 50.04 2.94 3. S AEZ 11.58 1.33 4. Clay 50.58 1.17 5.843 3. S AEZ 07.843 3.97 2.05 4.19 8.30 5.58 1.58 1.46 3. Clay 75.19 8.17 5.42 5.82 2. N AEZ 08.17 5.44 3.19 8.73 AP P E N D I X B — G E NE RAL SCE NARIO ASSUMP T IONS A ND A PPLICATION FOR WORLD REGIONS TABLE B. Clay 75.17 5.17 5. Clay 75.75 3.33 4.85 3. Clay 50.19 8.19 8.19 8. N AEZ 09.843 3.17 5.17 5.19 8. Clay 75 AEZ 07.843 .92 3. N AEZ 11.25 5.843 3.843 3.843 3.58 5.843 3. S AEZ 11.19 8. Clay 25 AEZ 03.05 2. Clay 75. Clay 75.19 8.843 3. Clay 25.17 5.843 3. Clay 25 AEZ 05.843 3.843 3. Clay 25 AEZ 06.32 4.19 8.19 8.19 8. S AEZ 09.19 8.94 2.43 4.58 1. N AEZ 10.03 3. S AEZ 11. N AEZ 10.19 8.86 3.58 1. Clay 25.19 8.83 5.58 1.19 8. Clay 25 AEZ 02.96 3.19 8. S AEZ 07.843 3. Clay 25.843 3. Clay 50. S AEZ 10.843 3.31 4.843 3.843 3.85 4.843 3.843 3. Clay 25.843 3.19 8. S AEZ 12.91 3.89 2. Clay 75.17 5.843 3.19 8. N AEZ 08.843 3.17 5. Clay 50 AEZ 03. N AEZ 08.843 3. Clay 25.58 5. Clay 75 AEZ 02.72 3.91 3.14 3.41 5.17 5.843 3.19 8.19 8. S AEZ 09.95 3. Clay 75.35 4.46 4.843 3. Clay 75.843 3.843 3.19 8.77 4. S AEZ 10. S AEZ 10.22 3.96 4. N AEZ 11. Clay 25.56 4. Clay 50 AEZ 04.58 1.17 5.47 3.53 4.843 3. Clay 75 AEZ 03.843 3.45 4.19 8.93 2.17 5.06 2.19 8. N AEZ 07.86 2. N AEZ 09. N AEZ 09.843 3.17 1.17 5. Clay 50.06 3.58 5.17 5.08 3. Clay 25 AEZ 12.55 4.65 4. Clay 50 AEZ 02.58 5.19 8.19 8.22 5.843 3.33 3. Clay 50.96 4.17 5.44 4.17 5.45 4.36 4. Clay 75. Clay 75 1.35 5.01 3. Clay 75.17 1.19 8.92 4. Clay 25 AEZ 04.843 3.19 8.72 4.41 4. Clay 75 AEZ 05. S AEZ 08.19 8.44 4.19 8. Clay 25. Clay 25 AEZ 01.08 3.17 5.03 2.843 3.843 3.94 4.19 8.19 8.39 4. N AEZ 10. Clay 75 AEZ 06. Clay 50 AEZ 06.46 2.5: C Inputs for Different Agroforestry Systems MAPPING UNIT (AFRICA) AGROFORESTRY GENERAL (tC/ha/YEAR) AEZ 01.17 5.19 LEGUME IMPROVED FALLOW + MAIZE (tC/ha/YEAR) 2.58 5.97 5.47 4.17 5.55 4. S AEZ 09.19 8.09 2.17 1.56 4.17 5.17 5.843 3. Clay 25.59 4.64 4.19 8.19 8.17 Source: This study. Clay 50.58 5.843 3. Note: AEZ = Agroecological Zone.19 8.843 3.843 3. EC O N O M I C A N D S E CT OR WORK COFFEE AND COCOA SHADE TREE SYSTEMS (tC/ha/YEAR) 8.27 3.19 8.843 3.843 3.98 4.19 8.17 5.843 3.19 8. Clay 50. S AEZ 08.36 4. S AEZ 08. Clay 75 AEZ 04.19 8.94 2.17 5.95 2.19 8.

UK CARBON SEQUESTRATION IN AGRICULTURAL SOILS . 1994). Voroney.. A. 2005b. The input value is based on organic inputs from tree-dominated fallow systems (Szott et al. and Sanchez 1991. subhumid.1). Due to the nonavailability of reliable spatial data of degraded lands in Africa. and semi-arid) (see Schroeder 1995. in which leguminous trees and coppiced trees and shrubs are grown in association with crops.. 1997. can sequester substantial amounts of C in plants and the soil. and Lemma et al.5. the mapping unit-specific maize residues were included as organic inputs in this system (mean residues of maize). Cajanus cajan. It is modeled for all areas classified as FAO Land Use System 13-18 (i. CAB International. 2006). and Senna siamea. and Sesbania sesban. The C inputs for the five agroforestry systems are shown in table B. The input values from the trees are mean values of the different tree species. REFERENCE Young. Wallingford. Szott. In addition. Fernandez. and Dossa et al. rain-fed agriculture. ƒ Legume improved fallow + maize: This system assumes a 2-year fallow period and a 1-year trees and maize period. Land Rehabilitation Land degradation may be defined as the long-term loss of ecosystem function and productivity caused by disturbances from which land cannot recover unaided. and irrigated agriculture) (see Figure B. and Kass 2005a. van Noordwijk et al. 2002. Improved Fallows + Maize Improved fallows.1). agro-pastoralism. Following a study by Kaonga and Coleman (2008). 2008).74 AP P E NDIX B — GENERA L SC ENA RIO A SS UMPTIONS A ND A PPLIC ATION FOR WORLD R EGIONS as mean values of more than 30 different systems taking into account different climate regions (humid. These two mitigation scenarios were modeled for all maize areas. Oelbermann. The tree species considered are Tephrosia vogelli. The tree species considered are Gliricidia sepium. It assumes combinations of improved perennial crop management (pruning and mulching) and the introduction of shade trees (see Szott. Agroforestry for soil management. Callliandra callothyrsus. and Sanchez 1991. The input values represent the mean annual input values over the whole system (fallow and cropping period).. Palm.e. Perennial Crop—Tree Systems This scenario considered two cash crops: coffee and cocoa. two improved fallow scenarios were modeled in association with maize. ƒ Coppiced improved fallow + maize: This system assumes a 3-year fallow period and a 7-year trees and maize period. the mitigation potential was applied to the FAO Land Use Systems 7-11 (herbaceous land-use systems in Figure B.

83 11Oceania 2.13 5.75 1.41 2.15 1.50 2.02 2Oceania 1.14 2.52 8Europe 2.42 2.26 3Russia 1.29 1.02 12South America 0. 50TH .50 3.42 4.92 1.33 1.18 1.55 2. AND HIGH BARLEY STRATUM LOW MEDIUM HIGH STRATUM LOW MEDIUM HIGH (Leer) 1.47 4.04 2.11 10South America 1.70 11Asia 0.11 1.44 3Oceania 2.98 6Africa 0.93 1.26 1.24 7Oceania 3.45 1Asia 1.58 1.86 1.19 2.35 1.22 1.06 1.45 5.71 1.41 9Middle America 0.56 0.72 3.83 4Asia 0.45 2.38 2Europe 1.97 1.69 8South America 1.56 7Russia 1.47 2. MEDIUM.63 2.21 2.60 4.59 1North America 2.99 1.80 4.92 2.96 2North America 3.35 1.1) GR OUPED INTO 25TH .77 7North America 3.81 2.22 4Africa 0.42 2.55 2.83 3.98 4.68 3South America 1.26 4.70 2.37 1.17 5Asia 0.79 3.61 2.51 1.92 2. A ND 75TH PER C ENTILE BINS Appendix C: GLOBAL CROP YIELDS (T HA -1 YR -1) GROUPED INTO 25TH.69 0.78 3.98 2.97 2.31 2South America 2.23 9Asia 1.61 1.89 2.35 2Asia 1.52 1.69 0.27 9South America 0.92 7Europe 3.60 5.02 1Russia 1.73 6South America 0.38 2.10 1.79 2.35 8Oceania 3.29 5.97 5.75 2Africa 0.06 2.70 0.81 1.70 3.78 6Asia 1.97 1.60 4.52 2.16 1.83 EC O N O M I C A N D S E CT OR WORK .16 4.18 3.99 1.87 7Africa 0.66 5Europe 2.75 AP P E N D I X C — G L OBAL CROP YIE L DS ( T HA.36 1.37 3Europe 1.99 4North America 3.26 3Asia 1.10 1.15 2.21 1. AND 75TH PERCENTILE BINS CORRESPONDING TO LOW.36 8Asia 2.69 1. 50TH.90 6North America 1.63 1.02 2.63 0.03 1.08 3.61 7Asia 2.86 4South America 0.56 1.73 1.10 3North America 2.58 2.1 YR.49 8North America 3.88 9Africa 1.73 1.81 3Africa 0.70 3.33 1.

78 0.67 1Russia 1.49 0.82 0.51 10Asia 0.77 0.87 0.99 1.13 1.93 1.92 1.80 3Oceania 1.74 0.76 7North America 1.58 0.94 1.73 0.02 6North America 0.13 12Asia 0.62 0.78 0.47 9North America 0.39 0.89 6Middle America 0.84 12Africa 0.19 3Europe 0.22 8Asia 0.98 1.67 0.28 1.46 1.36 2.46 1.44 1.54 11South America 1.83 1.86 2Europe 0.48 8Europe 2.37 0.08 CARBON SEQUESTRATION IN AGRICULTURAL SOILS .02 2.54 0.13 9Middle America 0.16 1.72 1.22 1.56 1.67 3Asia 1.54 11Africa 0.81 0.18 1North America 1.67 0.52 0.17 0.41 1.45 0.69 0.64 3South America 0. A ND 75TH PER C ENTILE B INS BEANS STRATUM LOW MEDIUM HIGH STRATUM LOW MEDIUM HIGH 10Africa 0.48 0.83 1.57 8South America 0.35 1.68 0.45 1.86 1.47 0.70 0.46 1.81 0.03 1.46 7Asia 0.93 1.82 0.17 6Africa 0.53 6South America 0.47 1.86 4.54 0.55 12Middle America 12South America 0.20 1.50 0.68 3North America 1.23 0.43 0.60 9Africa 0.81 4Africa 0.49 0.19 1.12 9Asia 0.92 2Oceania 1.71 0.09 1.84 1.79 7Russia 0.03 1.36 0.53 4North America 0.05 1.25 2South America 0.15 3.11 1.73 0.60 3Africa 0.87 1.99 1.92 7Africa 0.86 0.65 0.76 1.19 3.37 1.78 2.24 1.44 0.79 2North America 0.67 0.67 0.12 9South America 0. 50TH .39 0.60 1.47 11Asia 0.42 0.75 0.86 1.04 4South America 0.64 0.88 1.71 0.76 A PP E NDIX C — GL OBAL CROP YIE LD S (T H A -1 YR -1) GR OUPED INTO 25TH .76 1.61 0.24 1.08 8Oceania 1.32 0.98 1.20 7Oceania 0.36 1.87 3Russia 1.70 0.87 6Asia 0.92 1.21 5Asia 1.15 1.65 0.86 10South America 0.39 4.57 0.40 7Europe 3.55 0.50 4Middle America 0.04 1.56 2Asia 0.66 10Middle America 0.45 2Africa 0.86 1Asia 1.96 1.15 4Asia 0.71 1.54 0.94 1.

53 8.36 1.86 8North America 5.70 8Africa 3.04 2Oceania 3.18 1.82 1.86 4Middle America 0.35 7Africa 1.88 2.89 4.54 12South America 2.88 2.58 2Asia 0.23 2.21 1.56 2.44 7.75 0.62 7Asia 1.97 1Asia 4.15 1.77 9Africa 0.05 7North America 6.94 1.78 1.83 3Asia 3.84 1.02 3Africa 1.96 9.70 12Middle America 1.80 5.58 5.65 2Africa 1.12 7.85 2.00 1.16 4North America 1.84 2.50 1.26 2North America 1.29 5.10 8.82 5.73 5.18 3Europe 0.42 6South America 1.80 8Asia 2.35 2.73 3.42 7.67 1.34 0.02 2.32 3.11 2Africa 0.08 2.73 2North America 3.59 6.80 1.38 7.96 4Africa 0.05 3South America 2.67 0.35 7Asia 3.62 9Asia 0.66 0.18 MILLET EC O N O M I C A N D S E CT OR WORK .03 12Africa 0.92 1.04 2.96 8Asia 0.02 7Russia 2.95 6Africa 0.40 6.12 8Europe 4.79 0.54 3.26 3North America 1.34 0.96 9.88 1.52 3Europe 2.94 3.92 1.44 9North America 0.44 4.76 1North America 6.59 3.45 1. 50TH .08 10South America 1.52 2.01 1.14 10Asia 1.66 8South America 3.26 4.64 2.54 8. A ND 75TH PER C ENTILE BINS MAIZE STRATUM LOW MEDIUM HIGH STRATUM LOW MEDIUM HIGH 10Africa 0.81 6.06 1.82 4.43 1.25 8.49 3.98 4.26 1.05 1.21 3North America 6.81 1.95 1.23 1.53 4.19 2.29 6Asia 2.56 6.12 1.28 10.22 1.64 2.47 9South America 1.88 5.97 9Africa 0.85 5.38 2.42 2.39 0.86 5.43 1.56 0.35 11Asia 1.55 0.17 8.48 3.79 7.27 3.34 9.30 7.68 1.83 2.16 6.73 2Asia 0.33 4.03 1.78 2.78 7Europe 5.62 0.96 3.20 6Asia 0.83 1.37 2South America 4.79 1Asia 0.12 6Middle America 1.72 0.87 3.89 1.43 6Africa 0.23 3.41 STRATUM LOW MEDIUM HIGH STRATUM LOW MEDIUM HIGH 11Asia 1.20 5.54 3.77 AP P E N D I X C — G L OBAL CROP YIE L DS ( T HA.11 4.62 0.54 4Asia 0.66 11South America 3.55 2.60 2.1) GR OUPED INTO 25TH .75 5Asia 1.65 2.99 11Africa 1.84 1.31 12Asia 1.69 5.08 5Asia 3.22 1.89 3Africa 0.15 1.28 4.72 0.45 2Europe 6.61 3.88 0.89 8Oceania 6.49 9Middle America 1.54 10Middle America 0.66 0.11 2.41 1.1 YR.54 0.68 3.06 4Asia 1.90 1.93 1.99 3Asia 1.85 6North America 1.70 2.59 0.53 0.71 1.75 4South America 0.16 1.02 9Asia 1.88 2.46 6.57 0.50 3.30 4Africa 0.44 7.

97 6.71 4.20 4.96 7North America 6.70 4.93 4.14 9North America 1.49 5.63 9Middle America 0.51 0.84 2Europe 6.09 3.45 6.81 2South America 4.66 CARBON SEQUESTRATION IN AGRICULTURAL SOILS .72 7Asia 3.34 6.46 6Africa 0.38 8Asia 0.26 4.12 10Middle America 2.64 6Middle America 0.15 6.56 4Africa 0.57 6.07 3North America 3.36 6South America 1.33 1.57 4.05 4.30 8North America 4.70 0.04 2.48 0.68 12South America 2.19 1.54 5Asia 4.67 9Africa 1.53 3.96 3Europe 3.73 6.45 0.74 6.01 2South America 4.27 9.92 1Asia 3.30 3.21 8Oceania 2.77 7.02 3North America 9.10 1.70 6. 50TH .75 2.53 2Asia 0.14 3.74 4.58 3.98 2Oceania 8.43 2.15 3Africa 1.09 7Oceania 3.89 6.90 5.70 0.14 3.23 6.67 3South America 5.04 3Asia 3.90 4South America 0.12 4.26 3.59 3Asia 3.63 2Oceania 2.39 4.13 4.38 0.70 2Africa 0.19 6Asia 3.39 8.83 4.55 1.54 8.54 4.37 2.40 3.08 6.64 3.14 3.97 5.09 9Asia 2.64 1.70 3Russia 3.54 3.52 6.17 2.82 1.34 12Africa 1.42 6Middle America 3. A ND 75TH PER C ENTILE B INS 78 RICE SORGHUM STRATUM LOW MEDIUM HIGH STRATUM LOW MEDIUM HIGH 10Africa 1.33 5.36 2.43 4.28 4.42 4.45 3.33 4Middle America 0.52 3.60 2.89 1.18 3.32 4.50 5.07 2.67 2.94 1.94 6.66 3.19 7.18 6.68 2Middle America 0.08 3.43 2.62 1.70 0.70 8South America 4.23 7Russia 3.91 6.24 1.13 2.71 4South America 2.54 3.61 2.15 3Oceania 2.26 6.97 4.45 2.91 3.95 1.39 5.82 6North America 4.78 3.99 6.80 12Middle America 2.69 3.18 2.59 4.44 11Asia 2.05 3.31 7Europe 5.01 10South America 2.02 1.65 3.75 2.54 2.81 3.78 1.70 0.44 4.24 6.48 4.59 1.62 0.81 4Asia 1.15 8Europe 6.69 7.70 1Asia 5.38 4Africa 0.59 10South America 3.22 9.28 5Asia 3.93 9.75 4.56 2.29 9.82 2North America 2.31 12Asia 2.17 6South America 3.81 1.14 4North America 1.83 4.18 6Asia 0.60 3.79 5.58 0.66 4.79 9Middle America 2.79 3.55 4.78 9Asia 0.68 5.57 4Asia 0.45 4.20 3.79 9Africa 0.95 5.64 2.01 6.44 11Oceania 2.80 12South America 2.25 5.71 0.77 9South America 1.29 3.31 3.22 4.37 11Africa 0.91 3.60 4Middle America 2.16 3.A P P E NDIX C — GL OBAL CROP YIE LD S (T H A -1 YR -1) GR OUPED INTO 25TH .75 2Africa 4.02 1.46 6.84 1.74 0.33 2North America 7.62 2.90 3.05 11Asia 0.22 3.17 6.23 7North America 4.35 6.81 3.10 3.17 7Asia 5.18 8Asia 4.16 4North America 4.51 8South America 4.78 6North America 5.24 2.78 8.13 1.42 4.73 1.72 6Africa 1.27 10Asia 3.69 8North America 5.13 9South America 1.69 2.21 2Asia 2.38 3.23 2.26 5.71 6.85 3.16 2.80 1.13 3.37 5.77 1.

17 1.76 11South America 2.06 1.25 9North America 1.02 8North America 1.02 1.40 1.97 1.96 1.61 3.52 2.86 3.76 6South America 2.41 2.60 2.50 2Oceania 1.55 EC O N O M I C A N D S E CT OR WORK .59 5Asia 1.06 3.50 1.19 2.83 1.35 2.11 2.83 9Asia 1.35 9Middle America 1.44 2.46 1.21 2.46 2.27 7Europe 2.34 2Africa 1.27 4North America 0.25 6Asia 0.14 1.28 1.31 4Asia 0.47 2.07 2North America 1.26 9South America 2.13 2.34 1.1 YR.95 7Russia 1.77 2.81 2.19 10South America 2.02 1.86 1.00 1.77 1.75 0.89 3North America 2.45 2.55 2.55 12Asia 1.21 1.63 3Europe 1.50 9Africa 0.02 2South America 2.31 1.63 1.82 2.53 1.01 12South America 2.36 2Europe 2.1) GR OUPED INTO 25TH .35 2.90 8South America 2.34 2.96 3Asia 1. A ND 75TH PER C ENTILE BINS SOYBEANS STRATUM LOW MEDIUM HIGH STRATUM LOW MEDIUM HIGH 10Asia 1.91 11Asia 0.77 0.08 1.04 2.61 0.39 8Europe 2.13 1.72 1Asia 1.55 1.16 1.29 2.98 1.23 2.82 2Asia 0.80 2.06 1.07 1.55 8Oceania 1.24 1North America 1.33 2.97 4Africa 0.95 2.88 8Asia 1.56 2.79 2.40 2.10 1.31 1.18 2.09 1.45 1.37 2.51 0.48 6Africa 0.58 3South America 2.84 2.93 1.47 0.63 2.49 2.55 7North America 2.59 0.79 AP P E N D I X C — G L OBAL CROP YIE L DS ( T HA.06 1.69 1.75 1.95 4South America 1.70 0.35 7Asia 1. 50TH .98 2.74 1.04 2.

29 3.64 1Russia 1.87 3Oceania 1.80 4.85 1.03 9North America 1.42 7Africa 0.57 3Russia 1.30 3.25 3Asia 1.60 3.55 1.21 1.66 4.22 2.33 5Russia 0.68 2.86 Source: This study.32 3Europe 1.76 2.36 3.66 9Middle America 1.95 6North America 2.99 4North America 4.74 1.48 1.95 2. A ND 75TH PER C ENTILE B INS WHEAT STRATUM LOW MEDIUM HIGH STRATUM LOW MEDIUM HIGH 10Asia 1.55 3.55 1Asia 0.08 2Asia 1.58 9Africa 1.52 1.77 12South America 1. CARBON SEQUESTRATION IN AGRICULTURAL SOILS .15 7South America 4.80 A P P E NDIX C — GL OBAL CROP YIE LD S (T H A -1 YR -1) GR OUPED INTO 25TH .36 8South America 1.05 1.00 7North America 3.83 1.05 3.19 1.01 3.85 2.69 4Asia 1.56 1.02 1.70 3.08 7Russia 2.30 2.91 1North America 1.92 4.63 3.23 1.42 6Asia 1.92 2.36 11Asia 1.61 11South America 2.01 5.11 6.71 1.63 9South America 1.30 4.20 2.51 3Africa 0.31 4.29 4Africa 0.49 5Asia 1.67 3.27 5.52 2Oceania 1.06 1.08 3.61 2Africa 0.56 1.51 4.87 2.81 1. 50TH .70 7.67 1.05 1.20 2.83 2.68 0.31 11Oceania 2.66 3.28 3.19 7Europe 4.58 2.76 8Europe 2.46 5.61 3.70 1.08 4.05 5.75 3South America 1.69 2.10 2.41 2.10 2.24 2.00 1.87 1.48 2.68 1.99 9Asia 1.38 8Oceania 2.11 2.31 2Europe 1.96 1.74 2.46 7Asia 2.67 4.71 3.48 1.03 2.30 1.26 1.77 2.92 1.96 3.18 5Europe 2.19 2.38 2.62 3North America 1.82 2.07 3.09 1.16 8Africa 6.98 2.23 2.84 2.31 6.70 2.33 5.58 2.04 6South America 1.33 1.96 7Oceania 2.64 4.92 4South America 0.72 2.54 2South America 2.91 8North America 2.84 1.48 1.13 1.97 2.44 6Africa 1.48 8Asia 1.30 2.01 10South America 1.85 2.53 11Africa 1.41 1.72 2.27 2.39 2North America 1.

∂p is the standard deviation of the parameter p in year t.81 AP P E N D I X D — U NCE RTAINT Y ANALYSIS Appendix D: UNCERTAINTY ANALYSIS Uncertainty in the RothC soil carbon modeling was estimated following the adoption of Sustainable Agricultural Land Management methodology. For each of these 20 data points. Uncertainty analysis took place in two steps: Pmax = X p + 1. Pmax is the maximum value of the parameter at the 95 percent confidence interval. The minimum Pmin and maximum Pmax values of the confidence interval for the mean of the parameters X p were estimated as The analysis calculates the soil model response using the model input parameters with the upper and lower confidence levels. 2 × PRSt . EC O N O M I C A N D S E CT OR WORK Pmin = X p − 1.1). monthly precipitation. In this case. Thereafter. Twenty repetitions were selected randomly among the different scenarios and years for which SOC change values were modeled (table D. and 1. where SEp is the standard error in the mean of parameter p in year t. For each mapping unit. A precision of 15 percent at the 95-percent confidence level was chosen as the criterion for reliability. SEp is the standard error in the mean of parameter p in year t. t | .96 is the value of the cumulative normal distribution at the 95-percent confidence interval.96 × SE p 1. Carbon sequestration rates using the minimum and maximum values of the input parameters are given by PRSmin. respectively.96 × SE p where Pmin is the minimum value of the parameter at the 95 percent confidence interval. 2. np represents the total number of data points of a parameter used in this analysis for each mapping. t − PRSmin. the standard error in the mean was estimated using SE p = ∂p np . The range of model responses demonstrates the sensitivity of the soil modeling. and np is the number of samples used to calculate the mean and standard deviation of parameter p. the mean values and the standard deviation for the three parameters were calculated. The input parameters for which the uncertainty was estimated were minimum and maximum monthly temperatures. two separate models were done with the minimum and maximum values as model inputs. and clay content in percent of the soil. t. t and PRSmax. The uncertainty (UNC) in the output model was finally calculated as UNCt = | PRSmax.

8% AEZ06-50 75% Sorghum 2s 75% Residue + compost 2030 0.1% Source: This study.1% AEZ03-50 50% Sorghum 1s 50% Residue 2019 1.9% AEZ11-50 N 25% Barley 75% Residue 2034 10.1 percent.5% AEZ11-50 N 50% Wheat 25% Residue 2017 10.3% AEZ02-50 25% Millet 50% Residue 2014 2. Note: UNC = Uncertainty . The uncertainty ranges from below 1 percent to 26 percent with an average value of 5.7% AEZ09-50 N 75% Maize 25% Residue 2016 9.8% AEZ12-50 75% Maize 75% Residue + compost 2029 25.9% AEZ10-50 S 75% Maize 25% Residue + manure 2027 3.9% AEZ08-50 N 75% Maize 15% Baseline 2026 6.2% AEZ10-50 S 25% Maize 75% Residue 2020 3.9% AEZ07-50 S Mucuna Cover crop 2024 0.9% AEZ06-50 50% Sorghum 2s 15% Baseline 2021 1.7% AEZ11-50 N 50% Wheat 15% Baseline 2035 7.A PPEND IX D — UNCERTA INTY A NA LY S IS 82 TABLE D.3% AEZ09-50 S 75% Maize 25% Residue 2032 2. CARBON SEQUESTRATION IN AGRICULTURAL SOILS .0% AEZ04-50 75% Rice 2s 25% Residue + compost 2029 1.1: Uncertainty Analyses Using Random Samples from the Mitigation Scenarios SCENARIO MAPPING UNIT YIELD BIN CROP RESIDUE FRACTION MITIGATION SCENARIO YEAR UNC t AEZ01-50 50% Maize 1s 50% Residue 2012 2.5% AEZ06-50 50% Sorghum 1s 75% Residue 2025 0.6% Average: 5.9% AEZ10-50 S 50% Maize 75% Residue 2027 6. AEZ = Agroecological Zone.4% AEZ04-50 50% Maize 1s 75% Residue + compost 2019 2.5% AEZ06-50 50% Maize 2s 50% Residue 2025 1.

TABLE E. rotation intensification. manure. Terracing and sloping barriers were applied to 75 percent of this land area in equal proportion. Grassland The respective abatement rates for fertilizer. The difference between current (table E. and crop residue application.6 million ha were estimated as having erosion hazard in Africa. and rainwater harvesting were each applied to one-sixth of projected grassland area for each of the four IPCC scenarios for the continent by 2030 (table E. and 15 percent of projected tree crop area for the remaining two scenarios. and crop residue application.8 Asia 497. No-tillage was assumed to cover 2 percent of cropland area in the B1 and A1B scenarios. Rainwater harvesting was assumed applicable to 19.2).1 ASSUMPTIONS FOR DERIVING THE APPLICABLE MITIGATION AREA FOR THE LAND MANAGEMENT PRACTICES AFRICA Asia Cropland Cropland The difference between current (table E. Land devoted to intensive vegetables was assumed to increase by 15 percent under the B1 and B2 scenarios. and it was assumed to increase to 7 percent of current land area by 2030 for all scenarios. Two-thirds of this was applied to improved irrigation and rainwater harvesting in equal proportions. The remaining cropland area under each scenario was distributed evenly among inorganic fertilizer. cover crops. Tree-crop farming was projected to increase by the same proportion the entire cropland area for the continent increased for A1B and A2 (the more economic focus scenarios). cover crops. rotation diversification. 83 . but only 1 percent in the remaining two scenarios. Biochar was applied to only 15 percent of the applicable area for each agroforestry-related practice for each scenario.1: Estimated Cropland Area in the 2000s MILLION ha Africa 165. pasture establishment on degraded land.5 million ha under each scenario. The estimated irrigable area in Asia is 270 million ha.2) under each of the four IPCC scenarios was allocated to land-use and agroforestry-related land management practices in equal proportion. manure. while it was assumed to increase by the same proportion for total cropland area under the remaining two scenarios.1) and projected cropland area (table E. EC O N O M I C A N D S E CT OR WORK Current land area under biofertilizer is 29 million ha. About 3.1) and the projected cropland area (table E. manure. No-tillage is currently practiced on 3 percent of land in Asia. Organic soil restoration was applied to the estimated degraded peat land area of 13 million ha for each scenario. (2008).4 Latin America 110.2) under each of the four IPCC scenarios was allocated to land-use and agroforestry-related land management practices in equal proportion. Sustainable biochar application was assumed for 15 percent of current tree crop area for B1 and B2 scenarios. (2008). improved pastures. about 7 percent increase in potential irrigable area for 1990. The abatement rate for organic soil restoration was taken from Smith et al.3 Source: Based on Monfreda et al. The remaining cropland area under each scenario was distributed evenly among inorganic fertilizer. but by just 15 percent under the two other scenarios that are more environmentally focused. This was assumed to increase by 5 percent under scenarios A2 and B2 and by 6 percent under the remaining two scenarios.AP P E N D I X E — A S S UMP T IONS F OR DE RIVING T HE A PPLICA B LE MITIGATION A REA FOR TH E LA ND MA NA GEMENT Appendix E: E. rotation intensification.

Nilsson. E. Kluwer Academic Publishers.. Capo-chichi. Vlek. Buendia. cover crops. grazing management.. B... The potential irrigable area is 77. Institute for Global Environmental Strategies. M. R. J. Gama-Rodrigues. Szabo. Muinga. 2011. Nutrient Cycling and Biological Nitrogen-Fixation in Agroforestry Systems.2 826. Kaizzi. Latin America Cropland The difference between current (table E. Agroforestry Systems 81 (3): 191–193. CARBON SEQUESTRATION IN AGRICULTURAL SOILS .2 384. Sandoval.. Geographic Distribution of Crop Areas.. Physiological Types. Ssali. T. Kleja. L.. and annual-to-perennial grass were each applied to one-seventh of projected grassland area for each of the four IPCC scenarios continents by 2030 (table E. rotation intensification. “Aboveand Below-Ground Carbon Inputs in 19-. R. M. P. “Farming the Planet: 2. C.4 Latin America 351. M. I.. 2005. J.” Tropical and Subtropical Agroecosystems 1 (2-3): 329–343. A.” Agroforestry Systems 72: 103–115. N. and Persistence of an Early and Late Maturing Mucuna Variety in the Forest-Savannah Transitional Tone of Ghana. Nutrient and Carbon Stock Contrasting an Open Grown and a Shade Coffee Plantation.1 361. C. Lemma.. Anthofer J. M. R. Ngara.” Agriculture.4 891.7 943. Carsky. L. and Teixeira. rainwater harvesting. Myhrman.. M.. “Modelling Soil Organic Carbon Turnover in Improved Fallows in Eastern Zambia Using the RothC-26. The remaining cropland area under each scenario was distributed evenly among manure. 2006. manure. H. D. ed. Miwa. Ezui K.. Philosophical Transactions of the Royal Society B 363: 789–813. 2008.0 282. 2006 IPCC Guidelines for National Greenhouse Gas Inventories.4 321. F. Barahona. J. J. Sustainable biochar production was assumed applicable to 30 percent of the agroforestry area in each scenario. Fernandes. M...2) under each of the four IPCC scenarios was allocated to land-use and agroforestry-related land management practices in equal proportion. B. P.L. No-tillage is currently practiced on 50 Mha. G. M. A.3 Model. M. Z. K.. Ecosystems. 2008.” Agriculture.0 Source: Based on Smith et al. Twothirds of this was applied to improved irrigation and rainwater harvesting in equal proportions.9 847. Janssen. C..6 714. rainwater harvesting. and Coleman.3 678. Tanabe.1) and projected cropland area (table E.. M.8 295. C.7 871. The Netherlands. K. D... R. grazing management. and annual-to-perennial grass were each applied to oneeighth of projected grassland area for each of the four IPCC scenarios on the continent by 2030 (table E. Bressani.2: Estimated Cropland and Grassland Area by 2030 (Million ha) B1 A1B B2 A2 CROPLAND GRASSLAND CROPLAND GRASSLAND CROPLAND GRASSLAND CROPLAND GRASSLAND Africa 279.7 271. and Environment 104 (3): 359–377..3 863. Gordon. R. et al. 2008.” Geoderma 136: 886–898. cropland–to-pasture. and Net Primary Production in the Year 2000. “Carbon Sequestration in Tropical and Temperate Agroforestry Systems: A Review With Examples From Costa Rica and Southern Canada. Nutrients. residue.and Below-Ground Biomass. Dordrecht. Japan. Reid W. improved irrigation.4 701. 2004. Dossa. N. Carew. “Above-Ground Biomass.. Oelbermann.. Olsson. P...3 426. Monfreda. Kass.. L.9 Asia 799. Cai. REFERENCES Oelbermann. Green Manure/Cover Crop Systems of Smallholder Farmers. Voroney. Voroney.2). “Differential Use and Benefits of Velvet Bean (Mucuna Pruriens Var. Kaonga. improved irrigation. Antonio C. D. pasture establishment on degraded land.5 325. Intergovernmental Panel on Climate Change.84 A P P E NDIX E — ASSUMP T IONS F OR DER IVING TH E A PPLIC A B LE MITIGATION A REA FOR TH E LA ND MA NA GEM ENT TABLE E. 2005a. Eggleston. (2008). Martino. Grassland The respective abatement rates for fertilizer.. L. and Kroschel J. and K.2). S. 2005b. “Soil Carbon Sequestration Under Different Exotic Tree Species in the Southwestern Highlands of Ethiopia. ed.0 414. “Soil Organic Matter. Smith. L. and Environment 105 (1-2): 163–172. A. P. R. L.” Global Biogeochemical Cycles 22: GB1022. and Foley. This was assumed to increase to 66 Mha under each scenario by 2030. Grassland The respective abatement rates for manure. and 4-year-old Costa Rican Alley Cropping Systems. E. “Future Agenda for Mucuna Research and Promotion. Ramankutty. Uganda. H. K. C. Eilittä et al. B. pasture establishment on degraded land. A.7 813. and diversification. 10-. and Environment 110: 59–77. cropland–to-pasture.. Eilittä. M. 2006. Ecosystems.. “Above.” Agriculture. Utilis) and N Fertilizers in Maize Production in Contrasting Agro-Ecological Zones of E. et al. 2008.8 Mha... 2006.” Forest Ecology and Management 256 (5): 1160–1166.6 358.3 656. Yields. Ecosystems.. Mureithi.” Agricultural Systems 88: 44–60. S. “Greenhouse Gas Mitigation in Agriculture.

Farida. L. C.” Advances in Agronomy 45: 275–301. Akhtar. M. Szott. C. “Carbon Stock Assessment for a Forestto-Coffee Conversion Landscape in Sumber-Jaya (Lampunh. T.AP P E N D I X E — A S S UMP T IONS F OR DE RIVING T HE A PPLICA B LE MITIGATION A REA FOR TH E LA ND MA NA GEMENT Szott. M. Hairiah.” Pakistan Journal of Botany 42 (5): 3125–3135. “Agroforestry in Arid Soils of the Humid Tropics.. 1991. S. Yaqub. E..) Wilczek] as a Grain Legume in the Annual Rice-Wheat Double Cropping System. 2002..” Science in China (Series C) 45: 76–86. Iqbal.. and Ali. C. Palm. A.. “Induction of Mungbean [Vigna Radiata (L. T. and Sanchez. Indonesia). A. M.. M. L. L. A... Forest Ecology Management 45: 127–152.. Rahayu. C. 1994.. and Verbist. P. and Davey... Soil plant interaction in agroforestry system. Y. “Biomass and Litter Accumulation Under Managed and Natural Tropical Fallows. C. T. T. S. 1991.. Wulan. A. 85 . M. B. B. EC O N O M I C A N D S E CT OR WORK van Noordwijk. Mahmood.. K. Sanchez. Szott. Fernandez & P.” Forest Ecology and Management 67: 177–190. M. 2010. A. Palm.

.

A G R I C U L T U R E Agriculture and Rural Development (ARD) 1818 H Street. NW Washington. D. 20433 USA Telephone: 202-477-1000 Internet: www.C.org/ard A N D R U R A L D E V E L O P M E N T .worldbank.