Okra performance and soil and water conservation as influenced by poultry manure and organic mulch amendments

There is growing interest in intensive dry season vegetable crop cultivation by peasant farmers in south eastern Nigeria, but little research information to guide them on appropriate soil and water management for restoring, replenishing, conserving and maintaining soil fertility for optimum profit on their fragile soils. A two-year field experiment was conducted during the dry seasons of 2009/2010 and 2010/2011 on the acidic coastal plain soils at Calabar, to evaluate various rates of poultry manure (PM) (0, 5, 10 and 15 t/ha) and organic mulch (0, 2, 4 and 6 t/ha) for optimum yield of okra (Abelmoschus esculentus L. Moench) and their combined effect on weed growth and soil chemical and physical properties. The PM and mulch application reduced soil bulk density, increased soil moisture retention capacity and lowered weed infestation. They also raised the soil pH, organic matter content, total N, available P and exchangeable K, Ca and Mg status of the soil. The growth and fresh pod yield of okra peaked at 10 t/ha PM and 4 t/ha mulch rates. These rates increased fresh pod weight by 94 and 57% and mean fresh pod yield by 160 and 115%, respectively, compared with the unamended control plots. Poultry manure at 10 t/ha plus 4 t/ha organic mulch had the best effects on soil bulk density reduction and fresh pod yield of okra.