Effects of Form and Method of Phosphate Fertilizer Application on Maize, Sorghum And Millet Growth in a Semi-Arid Environment Of Kenya. I. Effect on Maize and Sorghum

Abstract

In a study to investigate maize and sorghum response to three types of phosphate fertilizers (DAP, TSP and SSP), uniform crop emergence and rapid growth to maturity resulted mainly from adequate rainfall, evenly distributed over the major development stages (vegetative, f10weringlsilking and grain filling). At harvest, the crops attained the highest grain yield of 2,970 and 2,250 kglha for maize and sorghum respectively. Grain yield levels from banding or broadcasting P were statistically similar for the two cereals, which implies that a farmer may select anyone of the methods for fertilizer P application. Phosphate fertilizers (DAP, BP and SSP) did not give significant grain yield increases, possibly as a result of adequate available P levels in soils on the test site (31 ppm P by Bray No 2 extraction). Moreover, with sorghum, grain yeild reduction from fertilizer applications were observed and the cause of yield depression has to be sought. The differences in performance of three P sources with respect to maize and sorghum production were evident mainly from the vegetative to f10weringlsilking stages of growth. In this period, rapid uptake of P and subsequent high dry matter yield of tops were observed from the highly soluble DAP. But the use of super phosphate (TSP and SSP) seemed to give higher final grain yield. Further studies are suggested in semi-arid areas (particularly in P deficient soils) to establish the economical levels of P application, suitable forms of phosphate and to identify easier and effective methods of P application.