Tillage and Fertilizer Effects in Sole Maize Cropping in a Degraded Nigerian Alfisol.
Vincent O. Aduramigba-Modupe, Institute Of Agriculutral Research And Training, Obafemi Awolowo Univ, Moor Plantation, PMB 5029, Ibadan, Nigeria and Omololu J. Idowu, Department of Crop & Soil Sciences, Cornell University, 1015 Bradfield Hall, Ithaca, NY 14853.
The knowledge of appropriate tillage is crucial for a reliable estimation of soil management purpose. A 2-year field study in a degraded alfisol in Ibadan (south west Nigeria), was conducted to determine the effects of four Tillage Systems (TS): (plow + harrow, plow, chisel + harrow and chisel) and three fertilizer NPK rates (0, 40 and 80 kg ha-1) on maize yields. The most variable data were root length, grain yield and hundred seed weight. Plow and harrow TS had the longest root (23.1cm), which was 38% and 28% significantly longer than chiseling and chiseling + harrowing. Root length decreased which fertilizer rates in all systems (except chisel + harrow). Grain yield showed significant increase only with fertilizer rates; over 1.4 Mg ha-1 was obtained when 0 NPK kg ha-1 was combined with plow + harrow TS; plow alone had grain yields of 1.9 and 2.0 Mg ha-1 with 40 and 80 kg NPK kg ha-1 rates. Only hundred seed weight significantly responded to TS by fertilizer interactions. From the results, plowing TS combined with 40 NPK kg ha-1 seems sufficient for maize production.