ABSTRACT
Acknowledgments ..................................................................................................................... 287
References ................................................................................................................................... 287
Low soil fertility is increasingly recognized as a fundamental biophysical cause for
declining food security among small-farm households in sub-Saharan Africa (SSA)
(Sanchez et al., 1997). Because maize is the staple food crop in most of southern Africa, it
will be our focus in this chapter. In 1993, SSA produced 26 million metric tons of maize on
approximately 20 m ha; approximately 54 million metric tons is expected to be needed by
2020. Meeting this maize production goal will depend on sustaining and improving soil
fertility levels that have been declining in recent years.
