Soil development and fertility characteristics of a volcanic slope in Mindanao, the Philippines

• Published in: Soil Science Society of America journal Vol. 63; no. 5; pp. 1258 - 1273
• Main Authors: Poudel, D.D, West, L.T
• Format: Journal Article
• Language: English
• Published: Madison Soil Science Society 01-09-1999; Soil Science Society of America; American Society of Agronomy
• Subjects: Agronomy. Soil science and plant productions; Alluvial terraces; Biological and medical sciences; characterization; Earth sciences; Earth, ocean, space; Exact sciences and technology; Fertility; Fundamental and applied biological sciences. Psychology; General agronomy. Plant production; Inceptisols; landscape position; mineralogy; Mountains; Oxisols; physicochemical properties; sloping land; soil fertility; soil formation; Soil genesis; soil morphological features; soil morphology; soil properties; Soil science; Soil surveys, classification and mapping, soil genesis; Soil-plant relationships. Soil fertility; Soil-plant relationships. Soil fertility. Fertilization. Amendments; Soils; Surficial geology; topography; Ultisols; volcanic ash soils; Volcanoes; Philippines; Asia; Philippine Islands; South east Asia; Mindanao Philippines; Phosphates; Slopes; Soil fertility; Available nutrient; Developing countries; Mineral composition; Ion composition; Tropical soil; SOIL RESOURCES; Mountain; Topography; Watershed; Chemical composition; Ultisols; Natural resources; Saturation; Property of soil; Chemical base; Exchangeable cation; Oxisols; Sorption; Volcano; Resource repartition; Terrace; Pedology; Cation exchange capacity; Regional study; Fixation; Volcanic soils; Soil genesis; Inceptisols; Potassium; Physicochemical properties
• ISSN: 0361-5995; 1435-0661
• DOI: 10.2136/sssaj1999.6351258x

Thirteen pedons representing the mountains, the upper footslopes, the lower footslopes, and the alluvial terraces of a volcanic slope in Mindanao, the Philippines were studied to understand relationships between the degree of soil development and fertility characteristics. Soils in the upper and the lower foot slopes were Oxisols as were soils in the alluvial terraces, while those in the mountains were Ultisols and Inceptisols. Presence of "amorphous components", such as allophane and imogolite, in all the pedons studied was indicated by a > 9.4 soil pH in NaF. Halloysite, gibbsite, goethite, hematite, and cristoballite were more common minerals in the clay fraction. Surface layers of all the pedons were slightly acidic and pH increased by depth. Phosphate sorption maxima ranged from 6944 to 14208 micrograms P g(-1), and it was closely associated with oxalate-extractable Al (Al(o)) and clay content. Inceptisols had higher phosphate sorption maxima than Oxisols. Soil samples representing the mountains showed the lowest level of both the available K and the potential buffering capacity for K (PBC(K)), while the upper footslopes had the highest level of available K. The PBC(K) values were lower for Inceptisols than for Oxisols, and they were found to be positively correlated with soil pH. There was a large difference between the cation-exchange capacity (CEC) and the effective cation-exchange capacity (ECEC), an indication of a large pH-dependent charge. Mountain soils showed lower base saturation than soils representing the upper footslopes, the lower footslopes, and the alluvial terraces.