Estimating the Impacts of Land Degradation on Changes in Crop Yields and Soil Carbon Stocks in Sub-Saharan Africa.

The objective of this study was to model spatial and temporal trends of agronomic and environmental indicators associated with land degradation under scenarios of both business as usual and integrated soil fertility management practices. We focused on quantifying the impacts of three land degradation processes - water and wind erosions, soil nutrient mining, and salinization - on changes in crop yields and soil carbon stocks that could be further incorporated into an econometric model to quantify the economics of land degradation. To accomplish this objective, we developed a modeling framework where empirical findings are coupled with a process-based model, national and global statistics databases, and remote sensing data. As a case study, we applied this modeling framework to Sub-Saharan Africa where crop yield reductions and soil carbon losses related to three land degradation processes were estimated at spatial resolution of a 30 min latitude by 30 min longitude grid cell for the historical period of 1981 to 2010.