Characteristics of soils derived from ultramafic rocks in Homonhon Island, Philippines

photo0091Miguel Francisco B. Abulencia and Faustino P. Villamayor, 2013 *( 


The prevalence of mining activities in Homonhon Island, Philippines has affected the soil resources and the agricultural livelihood of the people in the island. Thus, this study aims to determine the physical and chemical properties of the soils and recommend suitable tree species for revegetating the area.

Five pits representing specific positions in the hillslope (i.e., summit, shoulder, backslope, footslope, and toeslope) were selected and representative soil samples from each horizon of the pit were collected for analyses following standard procedures.

Soils have pH values ranging from 5.5 – 6.8 and low potential CEC values of <34 cmol(+)/kg with the presence of kandic horizon in all soils except for the backslope which has cambic horizon. Moreover, soils generally have decreasing organic matter content and available P with increasing depth. All the soils except for the backslope are classified as Kandiudults while the backslope qualified as a Dystrudept.

Acid-tolerant species such as Piliostigma malabaricum is suitable in the area. Morover, no-tillage and or contour hedgerow can be applied in the hillslope so as to minimize soil erosion. Addition of organic materials through green manuring is beneficial as it does not only promote aggregation but also serve as a source for nutrients.

keywords: ultramafic rocks, mining activities, Piliostigma malabarcium


Mineral Nutrient Contents of Soil and plant tissues of Abaca (Musa textilis.Nee) in areas infected with the Abaca Bunchy Top Virus (ABTV) in Leyte and Southern leyte

3Jertz Vlyn D. Escala* and Romel B. Armecin, 2013 *(


This study was conducted in the different abaca growing areas in Leyte and Southern Leyte infected with abaca bunchy top virus (ABTV).  This was done to assess the biomass, nutrient availability, nutrient status, and evaluate the amount of nutrient present in the plant tissues of non-infected and infected plants.  Soil and tissue samples were collected in the different abaca growing areas and these were brought to the laboratory for analysis.

Among the sites sampled, % ABTV infection was higher in Ormoc site and the biomass was higher in non-infected than the infected plants.  Phosphorus and magnesium contents of soil and plant tissues in Ormoc site were low while potassium (K) and iron (Fe) contents were higher.  Nitrogen (N), phosphorus (P), calcium (Ca), magnesium (Mg) and manganese (Mn) were higher in concentration in the leaf tissues. Pseudostem tissue had higher concentration of P and Ca while iron (Fe) and zinc (Zn) in corm tissue.  This finding suggests that ABTV infection reduce the biomass of abaca. Low P and Mg in the soil could contribute to high incidence of infection.

Physical and chemical characteristics of soils from the landslide areas of Abuyog, Leyte

DSC09705Jorge P. Cabelin* and Beatriz C. Jadina, 2013 *(


The steep and unstable topography of Abuyog, Leyte and recent landslide occurrences in the area particularly in Canmarating and Tadoc justifies the need for soil characterization of the landslide areas of the place. This research was conducted to determine the physical and chemical properties of soils from the landslide areas in Abuyog,  Leyte and relate these to landslide occurrences.  Two landslide cuts from different sites were evaluated using representative soil profiles which were examined in the field and sampled for the analysis of physical properties including particle size distribution, bulk density, particle density, total soil wet density, porosity, field capacity and water holding capacity, hydraulic conductivity, Atterberg limit and some chemical properties including pH, organic matter content, cation exchange capacity, and exchangeable sodium content.

Soils from the two landslide areas in Abuyog, Leyte generally have clayey texture, low bulk density, high total soil wet density, average particle density, porosity, moderately high saturated hydraulic conductivity, high liquid limit, and plastic index with very strongly to moderately acidic pH, high organic matter in surface and low at subsurface layers, moderate CEC and exchangeable Na.

Keywords: landslide, physical, chemical, plastic limit, Atterberg limit

Nutrient status of selected degraded upland soils in Samar island

IMG_4925Leo Jude D. Villasica* and Victor B. Asio, 2013 *(


Due to the low productivity of degraded uplands, this study focused on the evaluation of the nutrient status of two degraded upland soils in Samar island namely, Brgy. Tulay, Sta. Rita, Western Samar and Brgy. Naparaan, Salcedo Eastern Samar. Soil monitoring plots were established in the farmer’s field planted to various crops. The soil nutrient status was evaluated by periodic sampling and analysis of the soil pH, OM, total N, available P, exchangeable bases, readily mineralizable C and N, plant nutrient concentration and microbial activity by soil respiration.

Results revealed that the nutrient status of the degraded uplands in Sta. Rita and Salcedo are low. In general, the low nutrient status is more severe in the Salcedo site than in the Sta. Rita site which is related to the more weathered nature of the former than the latter. Moreover, both sites have strongly acidic soil which is low in OM, total N, available P, and exchangeable bases contents. The low nutrient status of the soil is reflected by the low leaf concentration of the nutrients (N, P, K, Ca). Also, the low nutrient status is observable from the low respiration rate and low levels of readily mineralizable C and N. Considerable variations in nutrient status is observable under different vegetation covers.

Keywords: nutrient status, degraded uplands, vegetation cover, Samar Island