COMPARATIVE STUDY OF SOIL PROPERTIES FROM RESIDENTIAL AND RICE-FIELD-CONVERTED-TO-SUBDIVISION LAND AREAS IN NORTHERN PHILIPPINES

Abstract:

^1,2Donna Marie DM Gonong, ¹Joel T. Maquiling

¹ Geophysics Research Laboratory, Department of Physics, School of Science and Engineering

Ateneo de Manila University, Loyola Heights, Quezon City 1108 Philippines

² Faculty of Science, Technology, and Mathematics - College of Teacher Development

Philippine Normal University, Taft Avenue, Manila, 1000 Philippines

Knowledge of soil properties is useful in any investigation that focuses on human management of land resources. The soil is not an undifferentiated medium but is rather a dynamic one that is constantly in formation and undergoing transformation. In reality, soils are not only fine-grained material, it is a combination of several sizes of grain from coarse to finer particles. Geo-technical properties of soil such as liquid, shrinkage, and plastic limits, specific gravity, density index, permeability and shear strength affect the stability of built structures. The objective of this study is to conduct a preliminary investigation on the soil properties of residential land (R) and rice-field-converted-to-subdivision land (RFS) areas in the same town in Northern Philippines. Soil samples to a depth of about 30 cm were taken from each area and subjected to geo-technical soil analysis. These core soil samples were initially tested for particle aggregate sizes, specific gravity, liquid and plastic limits, and permeability. Results reveal that the RFS contained 95% aggregates finer than 75 μm while the R contained only 17% aggregates smaller than 75 μm. Moreover, the RFS was found to have a plastic index of about 27 while the R was approximately 0, and is therefore considered non-plastic. Specific gravity values are 2.09 for the RFS and 2.14 for the R. Permeability test results reveal a low permeability for the RFS and a medium permeability for the R. These results show that there should be considerable geo-technical research done on the prevalent practice of converting rice fields to low-cost subdivisions in Northern Philippines.

Key words: Soil properties, land resources, geotechnical properties, residential land, rice-field-converted-to-subdivision land, aggregate sizes, specific gravity, liquid and plastic limits, permeability, geotechnical research