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Soil carbon sequestration in small-scale farming systems: A case study from the Old Peanut Basin in Senegal Item Type text; Dissertation-Reproduction (electronic) Authors Tschakert, Petra Publisher The University of Arizona. Rights Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author. Download date 08/10/2021 21:41:57 Link to Item http://hdl.handle.net/10150/280333 SOIL CARBON SEQUESTRATION IN SMALL-SCALE FARMING SYSTEMS: A CASE STUDY FROM THE OLD PEANUT BASIN IN SENEGAL by Petra Tschakert Copyright © Petra Tschakert 2003 A Dissertation Submitted to the Faculty of the GRADUATE INTERDISCIPLINARY PROGRAM IN ARID LANDS RESOURCE SCIENCES In Partial Fulfillment of the Requirements For the Degree of DOCTOR OF PHILOSOPHY In the Graduate College THE UNIVERSITY OF ARIZONA 2 00 3 UMI Number: 3090025 Copyright 2003 by Tschakert, Petra All rights reserved. UMI UMI Microform 3090025 Copyright 2003 by ProQuest Information and Learning Company. All rights reserved. This microform edition is protected against unauthorized copying under Title 17, United States Code. ProQuest Information and Learning Company 300 North Zeeb Road P.O. Box 1346 Ann Arbor, Ml 48106-1346 2 THE UNIVERSITY OF ARIZONA ® GRADUATE COLLEGE As members of the Final Examination Committee, we certify that we have read the dissertation prepared by Petra Tschakert entitled Soil carbon sequestration in small-scale farming systems; A case study from the Old Peanut Basin in Senegal and reconnnend that it be accepted as fulfilling the dissertation requirement for the Degree of Doctor of Philosophy !" jo? Charles F. Hutch Date /// llchael" E. Bonine Date n S|.Bipn P.J. Batterbury Date I / y;/ i!/aj Diane E. Austin Date li-n- Si Mamadou A. Baro Date Final approval and acceptance of this dissertation is contingent upon the candidate's submission of the final copy of the dissertation to the Graduate College. I hereby certify that I have read this dissertation prepared under my direction and recommend that it be accepted as fulfilling the dissertation requirement. ^ Dissertation Director Date ^ Charles F. Hutchinson 3 STATEMENT BY AUTHOR This dissertation has been submitted in partial fulfillment of requirements for an advanced degree at The University of Arizona and is deposited in the University Library to be made available to borrowers under rules of the Library. Brief quotations from this dissertation are allowable without special permission, provided that accurate acknowledgment of source is made. Requests for permission for extended quotation from or reproduction of this manuscript in whole or in part may be granted by the copyright holder. SIGNED 4 ACKNOWLEDGEMENTS Passion, curiosity, a surprisingly resilient sense of adventure, the harsh beauty of African drylands, the dances in the villages - energetic, colorful, and mesmerizing - the spicy millet-cowpea-peanut dishes served at special occasions, the peaceful nights underneath the desert stars, the intensity of life as I have experienced it during both good and bad times en brousse, a perpetual desire to learn, to understand, and to grow, and the comfort and tranquility I found in my gingerbread house back in Tucson during long hours of writing all made this journey a truly fulfilling experience. I would like to thank my advisor Chuck Hutchinson, who originally stirred my interest in the topic, for his superb scientific guidance and subtle but omnipresent moral support. I am also grateful to Mike Bonine, Diane Austin, and Simon Batterbury for their interest in the complexity of the research and their critical comments on the manuscripts. Thanks to Tim Finan and Mamadou Baro for their watchful eye throughout the process. I am greatly indebted to Lennart Olsson, Larry Tieszen, Gray Tappan, Bill Parton, Dennis Ojima, and Steve DelGrosso for broadening my technical horizons. I am thankful to Chiyo Yamashita-Gill for her assistance, resourcefulness, and what I would call magic touch smoothing the way. Special thanks go to my Senegalese friends and colleagues, above all Agatha Thiaw, Djibril Diouf, Mamadou Khouma, and Modou Sene as well as the men, women, and children in the villages who have been a source of inspiration all along the way. Finally, I want to thank my family and friends, here and back home in Austria, for all their years of encouragement and solidarity. 5 DEDICATION Meinen Eltern fiir ihren Glauben an meine Kraft und Kreativitat. A tous ceux qui ont accepte Awa Mbengue conune une de leurs filles et soeurs. 6 TABLE OF CONTENTS Page LIST OF ILLUSTRATIONS 7 ABSTRACT 8 L INTRODUCTION 10 Context of the problem 10 Study area 14 Dissertation format 16 2. PRESENT STUDY 18 Summary 18 Conclusions 25 REFERENCES 28 APPENDIX A: Carbon for farmers; Assessing the potential for soil carbon sequestration in the Old Peanut Basin of Senegal 30 APPENDIX B: Cattle, crops and carbon: Prospects for carbon sequestration in smallholder farming systems in Senegal 75 APPENDIX C: The costs of soil carbon sequestration: An economic analysis for smallholder farming systems in Senegal 144 APPENDIX D: Sectors of the STELLA Model "Household Budget and Decision-Making in the Old Peanut Basin, Senegal" 203 APPENDIX E: Manual for soil and biomass carbon measurements in the Old Peanut Basin: Method and measurement results from November and December 2001 (in French and Wolof) 218 7 LIST OF ILLUSTRATIONS Page Figure 1 Diagram showing the research area and villages in the center of the Old Peanut Basin, Senegal 15 8 ABSTRACT Carbon sequestration in small-scale farming systems in semi-arid regions offers the possibility to increase local soil fertility, improve crop yields, enhance rural people's wellbeing, and strengthen the resilience of agricultural systems while reducing CO2 accumulation in the atmosphere and, thus, contributing to climate change mitigation. A variety of management practices and land use options have been proposed to increase carbon uptake and reduce system losses. So far, less attention has been paid to local smallholders, the ultimate agents of anticipated community carbon projects, and the complexity, diversity, and dynamics of their livelihoods in a highly variable and risk- prone environment. A hybrid research approach, combining biophysical, economic, cultural, and institutional analysis, was used to assess the potential for soil carbon sequestration in the Old Peanut Basin of Senegal. In situ soil and biomass measurements provided current carbon accounts. Historic carbon changes and future sequestration rates under various management practices were simulated with CENTURY, a biogeochemical model. The simulation results well represented general historic trends and carbon storage potential. However, they did not accurately reflect variable and flexible site- specific management strategies as farmers adapt to stress, shock, and crises over time. To account for these, distinct pathways of agricultural and environmental change were examined in Wolof and Serer villages and viable options for carbon sequestration were evaluated. Systems analysis was used to explore the various components that influence farmers' perceptions, choices, and decisions with respect to land management. Results 9 showed that resource endowment and institutional and policy incentives determine which carbon sequestration activities might be most appropriate for different groups of farmers. Finally, a cost-benefit analysis and a cash-flow analysis (using STELLA) were performed to assess the financial profitability and economic feasibility of proposed management strategies. The study reveals large differences in these measures between farmers with low and high resource endowments. In most cases, local smallholders are not likely to have the investment capital necessary to implement the alternative management practices. A farmer-centered approach to carbon sequestration, as proposed by the study, can be used to more effectively address the needs and capacities of smallholders in dryland carbon offset programs. 10 CHAPTER 1 INTRODUCTION Context of the problem African drylands, often portrayed as heavily degraded and eroded, have experienced environmental, economic, and political shocks and crises that have significantly altered small-scale farming systems and the ways rural stakeholders manage their resources. At the global level, carbon in the form of CO2 is accumulating in the atmosphere at an accelerated pace, primarily as a result of combustion of fossil fuels, tropical deforestation, and other types of land use changes around the world. By linking these two phenomena through carbon sequestration in soils, a possible win-win situation can be achieved that is anticipated to yield benefits for local smallholders in vulnerable dryland agro-ecosystems as well as the global society. Increasing the uptake of CO2 from the atmosphere through improved soil management practices and land use options on the ground will raise soil organic carbon, improve critical soil properties, enhance agricultural productivity, and contribute to the restoration of degraded or abandoned lands. As such, carbon sequestration in soils could constitute a crucial link between three international conventions: the UN Framework Convention on Climate Change (UNFCC), the UN Convention to Combat Desertification (UNCCD), and the UN Convention on Biodiversity