Effect of Mavuno Phosphorus-Based Fertilizer and Manure Application on Maize Grain and Stover Yields in Western Kenya

Abstract

Low crop productivity in western Kenya can be attributed to low soil fertility and limited use of organic and inorganic fertilizers. This is attributed to high costs of fertilizer, inconsistent application and duration of use. Efforts to improve and maintain soil productivity through use of manure and fertilizer among others has been ongoing in western Kenya for years. Despite these efforts low crop yield associated with limited use of common compound fertilizers is still prevalent. Remarkable increases in yield have been noted with compound fertilizers which offer additional benefits in terms of nutrient supply. Mavuno a locally blended fertilizer promoted in western Kenya offers such benefits. The objective of this study was to evaluate the effect of mavuno phosphorus-based fertilizer and manure on maize and stover yields in Nyalgunga, Nyabeda and Emusutwi sub-locations, western Kenya; where low soil fertility, coupled particularly with low available phosphorus  has been pointed out as the major factor limiting crop productivity.  The study was carried out on fields where mavuno fertilizer at 20kg P ha^-1 and manure at 2t ha^-1 has been applied for six years. A randomized block design was used and maize grain and stover yields calculated from the four treatment fields; control (no input), manure (2t ha^-1), mavuno (20kg P ha^-1) and manure (2t ha^-1) + mavuno (20kg P ha^-1). There was a remarkable increase in maize grain yield (control 904 kg ha ^-1, manure+ mavuno 2238 kg ha ^-1) a 148% increase in yield above control plot (p=<0.001) and stover yield (control 825 kg ha ^-1, manure+mavuno 1381 kg ha ^-1) a 67% increase above control plot (p=<0.001).  Mavuno phosphorus-based fertilizer and manure have a positive effect on maize grain and stover yield and can sustain soil productivity under long term use, their application in soils  improves availability of phosphorus to plants resulting in high yields and improved soil properties. Understanding the effect of continuous application of phosphorus-based fertilizers and manure is essential for sustaining soil productivity among small holder farms of western Kenya to meet the high food demand, which is currently forcing farmers to continuously grow maize on the same piece of land resulting to soil degradation.

Keywords: Mavuno, manure, Maize grain yield, Maize stover and Western Kenya