NNAH, M.B, IKPE, F.N., OSAKWE, J.A and MBONU, O.A.(2010). Influence of oil palm bunch refuse ash and urea on soil physic-chemical properties and okra yield in South-Eastern Nigeria. Acta Agronomica Nigeriana. Vol. 10(2):117 – 124.
Abstract:
A field trial was conducted at Korokoro Tai, Tai Local Government Area and the Teaching and Research Farm of the Rivers State University of Science and Technology, Nkpolu-Oroworukwo, Port Harcourt both in South-Easthern Nigeria to determine the influence of soil palm bunch refuse ash (OBRA) and urea (a nitrogenous fertilizer) on the soil physicochemical properties and yield of Okra. The trial was conducted on Typic paleudult of the coastal plain sands of Rivers State and the experiment was designed in a split plot fitted into a randomized complete block design. It was laid simutaneously in the early planting season (March to June) of 2009, with the main plots as the rates of O, 4and6tha’ of OBRA while the sub-plots were assigned urea levels of o,50,I00,150, AND 200kg ha’. Results showed that the soils were deficient in organic matter (OM), total nitrogen, magnesium and potassium with acidic reaction. The OBRA was relatively high in the cations and phosphorus but low in nitrogen with alkaline reaction of 8.5. OBRA and urea increased soil pH, Om, N, P Ca and Mg at harvest. The highest pod yield was measured in plots amended with 6t ha-1 OBRA/50kg N ha-1 as 7.55t ha-1 and 7.59t ha-1 at Korokoro Tai and UST respectively. This was followed by plots amended with 4t ha-1 OBRA/l00kg N ha-1 and 6.6t ha-1 OBRA/l00kg N h-1 at Korokoro Tai and UST respectively. Relative to the control the highest pod yield increased by 33%. The higher the number of pods, the higher the total pod weight. The application of OBRA, which contains a little amount of nitrogen, reduced the nitrogen requirement for the optimum yield of okra. The trend for almost all the yield parameters consistently showed that the higher the OBRA rate applied, the lower the N requirement of okra. Oil palm bunch refuse ash is therefore recommended with urea at the rate of 6t ha’ OBRA/50kg N ha-1 or 4t ha’ OBRA/100kgN ha-1 as soil amendment with great potentials to ameliorate the soil acidity and keep the soil more fertile with increase in available nutrients and maintenance of optimum pH.
Keywords: Oil palm bunch refuse ash, fertilizer, okra, yield, coastal plain sands.