Effect of Variation in Tillage Systems on Maize (Zea mays L.) Establishment and Grain Yield in a Semi-Arid Tropical Clima

On-farm experiments were designed to investigate the response of maize establishment and grain yield to variation in tillage systems. The tillage treatments included arara ploughing followed by zig-zag harrowing and arara ridging (T1); emcot ploughing followed by zig-zag harrowing and emcot ridging (T2); mouldboard ploughing followed by disc harrowing and mouldboard ridging (T3); disc ploughing followed by disc harrowing and disc ridging (T4); manual ridging (T5). Generally, shallow (0-15.0 cm) tilled plots of T1 showed lower root lengths and root length densities than deep (0.28.0 cm) tilled plots of T4. However, there was higher soil penetration resistance (PR) in T1 than in T4. Increased PR in the range of 4.0 – 4.5 MPa decreased plant height (Hp), leaf area index (LAI), and maize grain yield (Yg). Reductions in Yg in the range of 35 – 50% can be expected for a reduction in soil moisture contents from 24.2 – 15.7%, w/w. Tillage treatment significantly (P<0.01) affected Yg. However, there were no significant differences at P<0.05 in the emergence rate index (ERI), LAI and Yg for the interactions of nitrogen levels × planting methods × tillage treatments