1. Economic Potential for Soil Carbon Sequestration in the Nioro Region of Senegal’s Peanut Basin by John Antle, Bocar Diagana, Jetse Stoorvogel and Kara Gray NASA Scientific Workshop on Land Management for Carbon Sequestration Bamako, Mali 26-27 February 2004

2. Major biophysical problem in WA Sahel: land degradation, a severe constraint to food production Major socioeconomic problem: increasing food insecurity and poverty Policy issue: How to enhance the sustainability of agricultural production systems and reduce poverty? Option: Carbon sequestration with alleged potential for contributing to agricultural sustainability, poverty alleviation, GHG emission mitigation, etc

3. Extent of C potential: needs thorough - biophysical and - economic analysis Several important issues to consider in the assessment of this potential: - what policies to create incentives for C seq? - what technical potential to store SOC and how much economic returns to farmers? - which additional social benefits, or “co- benefits,… take account of full array of benefits and costs - how to design appropriate and efficient incentive mechanisms for soil C seq?

4. Economic feasibility of soil carbon sequestration Few studies outside the US Previous research in Senegal: Century model to predict carbon rates Evaluation of economic returns to practices No study combining biophysical and economic data and models to predict soil C sequestration at alternative C prices

5. Purpose of this study Report preliminary results from a simulation analysis applying the Tradeoffs Analysis Model to the peanut-millet production system in the Southern Peanut Basin of Senegal (Nioro) Derive C supply curves showing the economic potential to sequester soil C in this production system

6. Method: The Tradeoff Analysis Model The TOA Model is a GIS-based system designed to integrate disciplinary data and models to implement the Tradeoff Analysis approach.

7. TOA: a modular approach that integrates disciplinary data and models GIS DSSAT DBMS Leachp Survey Weather Economic models GIS DSSAT DBMS Leachp Policy Survey Weather Economic models GIS DSSAT DBMS Leachp User shell Survey Weather Economic models

8. Fig l: Integrated Assessment of Soil C Sequestration using the Tradeoffs Analysis Model

9. Study area and Data used Nioro: area in the Southern Peanut Basin Annual rainfall: about 750 mm average temperature: 27,5 °C millet and peanut: main crops grown in annual rotation small crop parcels Data Farm household and plot surveys conducted by ENEA in 2001. Sample: +100 households in thirteen villages of the Nioro administrative department

10. Fertilizer use in the Nioro sample Low fertilizer application rates More than half of the fields received mineral fertilizer on peanut and half for millet MilletPeanut Average amount used on fields receiving fertilizer (kg/ha) 52 54 % of fields receiving mineral fertilizer 4862

11. Technological and Policy scenarios Technological scenarios Traditional practice of low fertilizer use Contract: required use of at least 60 kg of active mineral fertilizer ingredient per ha The above combined with incorporation of additional crop residues in the soils. Policy scenarios: variation of Peanut producer price Carbon price

12. Crop residue management in Senegal High value as animal feed on and off-farm Costs of incorporation = foregone value of the crop residue as animal feed +additional labor costs associated with incorporation Incorporation: not a widely adopted practice most likely because of the factors above, but lack of reliable data to confirm this Add agricultural equipment constraint

13. Simulation Results

14. Total C production potential at alternate C prices

15. Sensitivity Analysis: effects of labor costs for crop residue incorporation

16. Participation in carbon contracts

17. Carbon rates vs Net returns

18. Conclusions TOA Model: integrated assessment of C sequestration potential in the Senegal Peanut Basin using biophysical and economic data models and simulation of carbon contract scenarios Main result: increasing fertilizer use alone would result in a low potential for soil carbon sequestration, but, combining increased fertilizer use and crop residue incorporation could result in the sequestration of marketable quantities of carbon. Need accurate and complete data for full costing of crop residue incorporation practice

19. Constraints and issues to address for a thorough analysis of soil carbon sequestration potential Farming practices Understand/alleviate constraints to increased fertilizer use Crop residue management: alternative uses Data needs Carbon stocks and rates Full costs and benefits of adopting practices that sequester soil C Institutional issues legal institutions: enforceability of contracts land tenure: property rights credit markets transaction costs

20. For further information on the Tradeoff Analysis Model, consult the following websites: www.tradeoffs.montana.edu www.tradeoffs.wur.nl Thanks for your attention!!!