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

Aims: The study was aimed to determine the edaphic qualities of two Long-Term Ecological Research (LTER) sites in Mindanao; Mt Apo in Cotabato and Mt. Hamiguitan in Davao Oriental, the Philippines Study Design: Random soil sampling within the plots Place and Duration of Study: Analyses of the soil samples collected from each site were performed at Soil and Plant Analysis Laboratory (SPAL), Central Mindanao University, Musuan, Bukidnon, the Philippines from October, 2012 to December 2013. Methodology: One hectare permanent plot was established in each site. Soil profile description was done in a pit measuring 1m wide, 1.5m long and 1m deep in each site. Soil samples for physicochemical characterization were collected within the plot. Soil physical properties included bulk density, particle density, soil texture and water holding capacity while the chemical properties included soil pH, organic matter, extractable P and exchangeable K contents using the methods employed at SPAL. Results: Results showed that the soils in Mt. Apo were extremely to very strongly acidic, had very high organic matter contents, slightly deficient to very deficient in extractable P, low to very high exchangeable K content, low particle and bulk density values, high porosity, moderate water holding capacity and moderately coarse to moderately fine-textured soils belonging to loamy textural class. On the other hand, the soils in Mt. Hamiguitan were slightly to very strongly acidic, contained adequate organic matter content, low extractable P, low exchangeable K, low particle and bulk density values, high porosity, moderate water holding capacity and are moderately fine to fine-textured belonging to loamy and clay textural classes. Generally, soils in Mt. Apo were more acidic but with relatively higher fertility status and comparable physical make-up with the soils in Mt. Hamiguitan. Conclusion: It was found that both sites have some soil constraints, particularly in terms of soil acidity and low nutrient availability to plants. Information obtained on this study revealed that identification of soil constraints are indispensable in formulating proper land use and conservation program.