Suzette B. Lina, Deejay S. Maranguit, Victor B. Asio, Jessie R. Sabijon, Kier Lambert B. Demain and Ariel B. Bolledo
Development of an integrated nutrient management strategy is needed to enhance soil quality and increase crop yields in the marginal uplands of Eastern Visayas. Due to very poor soil condition, a field fertilizer experiment using the combined application of organic and inorganic fertilizers was conducted in Inopacan, Leyte, to assess the growth performance of corn plants. The six treatment combinations used in this study were the following: T1 (no fertilizer added); T2 (National recommendation for corn at 90-60-60 kg N, P2O5, K2O ha-1); T3 (chicken dung at 15 tons ha-1); T4 (vermicast at 15 tons ha-1); T5 (1/2 of inorganic + chicken dung at 7.5 tons ha-1) and T6 (1/2 of inorganic + vermicast at 7.5 tons ha-1). Generally, application of organic fertilizer significantly increased soil pH, organic matter and total nitrogen. In addition, the treatments significantly increased, plant height, ear length, number of grains per ear, weight of 1,000 seeds, fresh stover yield, and grain yield of corn. Corn plants in plots applied with fertilizer following T2 (National Recommendation for corn at 90-60-60 kg N, P2O5, K2O ha-1) and T5 (1/2 of inorganic + chicken dung at 7.5 tons ha-1) grew taller and developed larger ears with more kernels per ear and heavier 1,000 seeds which resulted to higher grain yield. However, using inorganic fertilizer alone had the same effect on ear length, number of kernels per ear of those corn plants applied with combination of either chicken dung or vermicast and one-half of inorganic fertilizers. Plants in control plots and those amended with vermicast alone showed the least growth responses.
Keywords: Marginal upland soil, degraded soil, organic and inorganic fertilizer