Effect of Tillage Methods and Phosphorus Fertilization on Maize in the Humid Tropics1

Abstract

AbstractThe recent interest in the adoption of minimum tillage for crop production in the humid tropics for better soil and water conservation has raised questions concerning crop yield and nutrient absorption. There is lack of information on the most suitable method of P application with minimum tillage as compared to conventional tillage with tropical soils. The present study was therefore undertaken to investigate the interaction between soil tillage and P application methods on (a) P movement in the soil profile, (b) maize root distribution, (c) P content, and (d) maize yield.The experiment was conducted on Egbeda soil series (Oxic Paleustalf) in southern Nigeria in 1974 and 1975 using a split‐plot design with four replications. Conventional and minimum tillage were the main plots, P rates and placement were the sub‐plots.Root density of maize was increased with P application. There was a tendency of higher root concentration in the upper 10 cm of the soil surface with minimum tillage. Movement of broadcast P in the soil profile was observed to be slow with minimum tillage. However, broadcast, band, and hill methods of P application was observed to be equally effective in supplying adequate P to the maize crop at P rates of 20 kg P/ha on the Egbeda soil. Therefore, no effect of P placement method on maize yield was observed with both minimum and conventional tillage methods. The lower maize yield with minimum tillage in 1974 was attributed to early N‐ stress. In 1975 with 160 kg N/ha, maize yield was equal with conventional and minimum tillage methods.