The Effects of Phosphate Fertilizers and Manure on Maize Yields in South Western Kenya

ABSTRACT Phosphorus, nitrogen and Striga hermonthica are the major constraints to maize production in the Nyanza Province of Kenya. Field trials were conducted on-farm in Nyanza Province to investigate the effects of phosphate fertilizers and manure on maize yields. The experimental design was a Randomized Complete Block Design (RCBD) with maize as the test crop. The maize was top dressed with calcium ammonium nitrate (CAN) fertilizer at a uniform rate of 30 kg N/ha diammonium phosphate (DAP), Minjingu rock phosphate (MRP) and triple super phosphate (TSP) fertilizers were applied at 60 kg/ha P2O5, farmyard manure (FYM) at 10 t/ha and a non-phosphorus (P) treatment (control) plus lime only. Responses (P ≤ 0.01) from grain yield, total dry matter yield and harvest index to phosphate fertilizers and manure treatments were found. Nutrient uptake and removal by the crop increased (P ≤ 0.01) due to fertilizers and manure application. Phosphate fertilizers and manure application increased (P ≤ 0.01)) available soil P, agronomic phosphorus use efficiency (APUE) and Physiological P use efficiency (PPUE). The results indicate that phosphate fertilizers and manure applications are essential to improve maize yield and nutrient P use efficiency.