1Institute of Crop Science and Resource Conservation (INRES), Department of Plant Nutrition, University of Bonn, Karlrobert Kreiten Straße 13, 53115 Bonn, Germany.
2Africa Rice Center (AfricaRice), 01 BP 2031, Cotonou, Benin.
Low soil fertility and high weed infestation are the main culprits for the declining
maize production inWestern Kenya. Technology packages to address these
constraints exist, but their effectiveness is likely to be influenced by variability in soil
types and farm management practices in the region. Trials were conducted during the
2008/2009 cropping seasons to investigate the nutrient use efficiency and yield
response of maize to some recommended management options for smallholder
farmers on three dominant soil types ofWestern Kenyanamely Acrisol, Nitisol and
Ferralsol. Irrespective of seasons, average maize yields were highest on Nitisol (3.6
t ha-1) and lowest on Ferralsol (2.1 t ha-1). Maize yield gaps (difference between
potentially achievable and actual yields) differed by season and soils with 4-5 t ha-1
on Nitisol and about 6 t grain ha-1 on Acrisol and Ferralsol. On Nitisol, the largest
share of this yield gap (80%) was closed by the addition of mineral fertilizer, while
on Ferralsol, reduced tillage could close 25-60% of the yield gap. The highest
agronomic (13-39 kg grain kg-1 N) and physiological (50-160%) N use efficiencies
were obtained with mineral fertilizers, while the addition of organic amendments
resulted in the highest P use efficiency (15-154 kg grain kg-1 P), irrespective of soil
type and season. As soil types and management options differentially affect yields
and nutrient use efficiency of maize, there is a need for field-specific targeting of
technologies to address maize production constraints inWestern Kenya.