Soil

Soils are an important part of our natural environment and are essential in providing our food and fiber needs. On Guam and in many other parts of the Pacific, agriculture holds an important place in island culture. Issues related to soil and water pollution have become increasingly important for all Pacific islands as they experience growing populations and urban development. 

The soil science program is addressing many of these issues for Guam and the region with the objectives of improving agricultural production, reducing threats of environmental pollution and the importation of potential pests, and preserving natural soil resources.

Seventeen different soil series have been mapped on Guam and are described in the U.S. Natural Resources Service (U.S. Department of Agriculture) 1988 publication “Soil Survey of the Territory of Guam”.

The soils of Guam can be grouped into three primary categories: soils over limestone (pure or argillaceous), soils on volcanic uplands, and soils on bottomlands and coastal margins. The predominant location of limestone-derived soils is in northern Guam and the predominant location of volcanic soils is in southern Guam.

The shallow, limestone-derived Guam soil series covers approximately 24% of the total land area of the island of 55,445 hectares (214 square miles). Agricultural land use accounts for approximately one to three percent of the total land use of Guam.

Approximately 127 hectares (314 acres) of land are under cultivation each year. Approximately 16,545 hectares of land (30% of the total) on Guam are at risk for erosion unless close-growing vegetation is maintained. Severe erosion of the Akina soil series on Guam exposes an infertile subsoil restricting regrowth of vegetation.

Additional public institutions on Guam involved in soil science include the U.S. Natural Resources Conservation Service, the University of Guam Water and Energy Research Institute and the Guam Environmental Protection Agency.