Soil Properties, Okra Performance and Nutrient Compositions as Affected by Tillage and Maize Cob Ash

Alfisols, the dominant soil order in southwest Nigeria in which crops are grown possess unfavorable peculiarities such as low inherent fertility and acidity. These limitations can be ameliorated by tillage and organic manuring. Therefore, field experiments were conducted during the 2014 and 2015 cropping seasons to assess the effects of tillage methods and maize cob ash (MCA) on soil properties, yield, growth, mineral, and vitamin C contents of okra fruit. The experiment consisted of 3 × 3 factorial combinations of three tillage methods {zero – tillage ZT, manual ridging MR, and plowing plus harrowing P+H} and three rates (0.0, 3.0, and 6.0 t ha-1) of application of MCA. Tillage methods and MCA influenced soil physical and chemical properties, performance, mineral and vitamin C contents of okra fruit significantly. MCA increased soil K, Ca, Mg, okra yield, growth, mineral and vitamin C contents of okra fruits up to 3 t ha-1 level after which there was a decrease. The order of reducing bulk density and soil chemical properties, increasing porosity, yield, growth, mineral and vitamin C contents of okra was: ZT > MR > P+H. Tillage appears to be indispensable for sustainable okra production on Alfisol of southwest Nigeria. Growth and yield of okra in this study was dependent on soil physical properties and chemical properties such as pH, OM, N, and K. Combination of P+H and 3 t ha-1 MCA produced better yield, growth, mineral and vitamin C contents of okra compared with other combinations of tillage with MCA. Addition of MCA to either P+H or MR is important to reduce the limitation of acidity associated with tropical Alfisol.Key words : Tillage, maize cob ash, Alfisol, okra, vitamin C, bulk density, porosit