THE EFFECT OF PHOSPHATE APPLICATION TO COVER CROPS ON THE YIELDS OF SUCCEEDING MAIZE (<i>Zea mays</i> L.) ON A KANHAPLIC HAPLUSTALF IN NORTHERN GUINEA SAVANNA OF NIGERIA

Abstract

Phosphorus deficiency is a major constraint that limits food production in Nigeria, especially under acidic soil conditions. Presently, successful production of high nutrient requiring plants such as maize is only possible with the use of inorganic phosphate fertilizers that are very costly and often unavailable to the farmer. In an attempt to address this problem, field trials were conducted on a Kanhaplic Haplustalf at Samaru (11 o 11'N, 7o 38'E) to evaluate the response of ten (10) leguminous cover crops and maize to native and applied phosphate, and to evaluate the effects of these treatments on the performance and P nutrition of succeeding maize in a rotation. Among the cover crops evaluated, Crotalaria ochroleuca was the most P efficient in terms of total amount of above ground biomass per unit P taken up, while Phaseolus vulgaris was the least efficient. The yield of maize preceded by Lablab purpureus, Chamaecrista rotundifolia, and Mucuna pruriens was increased by over 50% in the first year after cover cropping. The positive effects of these cover crops on yield of succeeding maize did not however manifest in the second year. Effect of Sokoto Phosphate Rock (SPR) on maize yields and available soil P started manifesting only in the third year of cropping when the soil P was sufficiently depleted to force the dissolution of phosphate rock. Nigerian Journal of Soil Science Vol.4 2003: 25-34