Soil and crop responses to different tillage practices in a ferruginous soil in the Nigerian savanna

Abstract

Mechanical tillage is gaining prominence as a food production technique in the savanna region of Nigeria. A mechanical cultivation method was compared with a zero cultivation practice and the traditional cultivation method involving a hoe. Soil moisture content was significantly higher ( P = 0.05) under zero tillage than under mechanical tillage or traditional hoe tillage systems. The stability of aggregates less than 2-mm diameter and the mean equilibrium infiltration rates were significantly lower under mechanical tillage. No significant differences were found between zero tillage and manual tillage. Soil bulk densities in the 0–5-cm depth under zero tillage were significantly higher than under the other tillage systems due to the greater disturbance of soil in the latter. Below the 0–5-cm depth, differences in bulk densities between tillage treatments were not significant. Nutrient ion distribution in the soil varied with the tillage system. Total P and K levels were higher in the surface than in the sub-surface soils under zero tillage, but not under the other tillage systems. Mean maize grain yields (kg ha −1) and cotton lint yields (kg ha −1) under the 3 tillage systems were not significantly different ( P = 0.05). However, significant yield differences were observed in some years. Weed population was significantly greater ( P = 0.01) under zero tillage than under mechanical tillage.