ABSTRACT
Acknowledgments ..................................................................................................................... 270
References ................................................................................................................................... 271
Sustainable management of soil, water, and other natural resources is the most critical
challenge confronting agricultural research and development in sub-Saharan Africa (SSA).
Soil fertility decline is a multi-faceted problem and, in ecological parlance, a “slow
variable,” one that interacts pervasively over time with a wide range of other factors,
biological, and socio-economic. Sustainable agroecosystem management is not just a
matter of remedying deficiencies in soil nutrients. Impediments include mismatched
germplasm and faulty cropping system design, the multiple interactions of crops with
pests and diseases, reinforcing feedback effects between poverty and land degradation,
