Characteristics and Nutrient Status of Two Degraded Upland Soils in Samar, Philippines

Abstract

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.

Morphophysical and Nutrient Characteristics of Degraded Soils in Sta. Rita, Samar, Philippines

“…In terms of color development, SP1 and SP3 had colors ranging from brown to light yellowish-brown in the surface and yellowish-brown in the subsurface horizon. Similarly, it was previously observed that the color of the degraded soils in the area was dark yellowish-brown in the surface and light yellowishbrown in the subsurface (Asio et al, 2015). SP2 had colors ranging from dark yellowish-brown to light gray indicating a poorly drained soil that resulted in a reduced form of iron (Fe) oxides linked to the absence of oxygen.…”

“…Similarly, in the study of Asio et al (2014), it was reported that the dominant vegetation of the degraded uplands of Inopacan, Leyte consisted of the same plants, including Andropogon aciculatus ('Amorseco') and Calopogonium muconoides ('Malabatong'). All of the plants mentioned can be considered as indicators of degraded soil (Asio, 2007;Asio et al, 2014).…”

“…Likewise, based on the initial study of Asio et al (2015), degraded soils in Sta. Rita were well-developed possessing an Ap-AB-Bt-C horizonation.…”

“…This problem was initially studied and reported that the soil in the degraded upland of Sta. Rita, Samar showed a less severe degree of degradation and had low fertility status (Asio et al, 2015). Hence, there is an urgent need for onsite data on soil formation, nature and characteristics of degraded soils in the said area for the prediction and evaluation of the soil's response to intensive human activities and climate change, thereby improving the crop production.…”

Chemical and Physical Properties of Soils in Mt. Apo and Mt. Hamiguitan, Mindanao, the Philippines

“…It is directly related to the porosity and indirectly related to the bulk density. Furthermore, it is mainly influenced by the soil texture as it takes the pore volume to be filled and hold a certain water volume [26]. The water holding capacity of the surface soils in Mt.…”