The study evaluated the morpho-physical, chemical, and biological characteristics as well as the nutrient status of two degraded upland soils located in Sta. Rita, Western Samar and in Salcedo, Eastern Samar. Soil profiles were examined and soil erosion was determined. Composite soil and plant tissue samples were collected from different vegetation cover or crops planted by the farmers. All laboratory analyses were done following standard procedures. Results indicate that: 1) the Sta. Rita soil which is relatively younger than the Salcedo soil shows less severe degree of degradation than the Salcedo soil; 2) the nutrient status of the degraded upland soils in Sta. Rita and Salcedo are low; 3) the low nutrient status is more severe in the Salcedo than in the Sta. Rita ;4) both sites have strongly acidic soils which are low in OM, total N, and available P contents; 5) considerable variations in the soil nutrient status were observed under different vegetation covers or crops; 6) soil erosion the appears to be major soil degradation process in both degraded uplands; 7) the low nutrient concentrations in the tissues of the plants growing at the sites reflect the low nutrient status of the soils; and 8) bulk density, porosity, aggregate stability, soil pH, organic matter, and carbon dioxide evolution appear to be good indicators of soil degradation.

Improving the productivity of marginal lands greatly depends on good understanding of the characteristics of the soils. Published data on the nature and characteristics of soils in marginal uplands are still limited. This study was conducted to determine the morphological and physicochemical characteristics of soils in the marginal upland of Inopacan, Leyte. Five representative soil profiles located in different physiographic positions were examined and sampled. Results showed that the soils were derived from volcanic materials particularly andesite and basalt rocks. Well-developed soils were found on the summit position with the horizon sequence of Ap-Bt-BC while poorly developed soils occurred on the lower slope positions having Ap-AB-Bw-BC horizon sequence. Soils were found to be highly acidic with soil pH close to 5.0. Soil organic matter, total nitrogen and available P were low and decrease with soil depth. Exchangeable bases (Ca, Mg, K and Na) were high in most soil profiles. The results indicate that N and P fertilization as well as organic matter addition are crucial to increasing the productivity of the marginal upland soils. The marginal nature of the soils is the result of decades of unsustainable cultivation practices.

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, P2O, K5O 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, P2O, K5O 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.