Abstract:
Declining soil fertility is a major food production constraint in most smallholders who
rarely apply chemical fertilizers to the crops. Mucuna, a high yielding and N fixing legume
that is widely adapted to a range of agro-ecological zones has the potential to improve
maize yields in such systems. Integration of mucuna into such systems may involve
management strategies that optimize complementary resource use ill the system. The
strategy used was staggering the relative planting time of mucuna in maize intercrop. The
work was done in the upper midlands of Kenya at Kabete and Embu for eight seasons from
2001 to 2005. Maize yield was not affected by inter-planting with mucuna but mucuna
biomass in the intercrop was 75% lower than in the sole crop. Delayed planting reduced
mucuna biomass significantly but planting density did not have a significant effect on
biomass production possibly because of compensatory growth. Maize had a comparative
advantage over mucuna in light and water capture because it grew faster and taller and
had a much larger root system than mucuna and therefore intercropping only reduced
mucuna biomass. Although intercropping maize and mucuna improved land productivity
when seasonal rainfall exceeded 300 rnm, the amount of biomass produced did not
improve maize yields in the subsequent season. Pure cropped mucuna stands produced the
highest amount ofbiomass, indicating that maize-mucuna rotation could supply adequate
amounts ofbiomass for a subsequent maize crop.