| dc.description.abstract | Due to escalating costs of imported fertilizers, there is renewed interest in the use of local nutrient resources
in managing soil fertility in Kenya. We tested the effect of two organic materials, farmyard manure (FYM)
and Tithonia diversifolia (tithonia), and an inorganic N fertilizer, urea, when applied alone or in combination
with three inorganic P sources, triple superphosphate (TSP), Minjingu phosphate rock (MPR) and Busumbu
phosphate rock (BPR), on maize yields and financial benefits. The study was conducted for three consecutive
seasons, from March 2007 to August 2008 in western Kenya. FYM and tithonia were applied to supply
20 kg P ha−1 in treatments where they were used either alone or in combination with the inorganic P
sources while 40 kg P ha−1 was from the inorganic P sources in the combination. Where urea was used,
the inorganic P sources were applied at 60 kg P ha−1. When applied in combination with urea, MPR
was a better P source for maize than TSP or BPR. However, when applied in combination with FYM or
tithonia, TSP was the best P source. Treatments including tithonia were more effective in increasing maize
yields than those without it with a similar total P application rate. The agronomic effectiveness of tithonia
did not, however, translate to economic attractiveness, mainly due to very high labour costs associated with
its use. FYM when applied alone at 20 kg P ha−1 was the only treatment that exceeded a benefit:cost ratio
of 2 and, therefore, the most likely, of the tested technologies to be adopted by farmers. | en_US |
