Sub-Saharan Africa faces huge food
supply challenges due to increasing human population,
limited opportunities to increase arable
land, and declining yields associated with continuously
declining soil fertility. To cater for their
food requirements, smallholders use only modest
levels of inorganic fertilizers and rely to a large
extent on manure, which is generally of low
quality. To explore factors influencing fertilizer
and manure use at the farm level, 253 farm
households in Vihiga district of western Kenya
were sampled. A pair of Tobit models was used to
relate amounts of manure and fertilizer used to
household variables. The results indicate that the
use of both manure and fertilizer reciprocally
influence each other and are strongly influenced
by household factors, and also imply that manure
and fertilizer uses are endogenous. Policy changes
are required to (1) reduce the burden on farming
alone in rural areas; (2) promote the use of
higher-cost, higher-value inputs such as fertilizers;
(3) improve access to input and output markets;
and (4) encourage farmer education so as to
promote sustainable soil fertility management.
Improved understanding of the biophysical and
socioeconomic environment of smallholder systems
can help target sustainable soil fertility
interventions more appropriately.