Northern Guam geospatial information server

Soil of northern Guam

Soil is unconsolidated natural matter on the immediate surface of the earth. It is a mixture of rock fragments, minerals, organic matter, water, and other materials and serves as a natural medium for the growth of plants. It forms through disintegration of rocks by physical, chemical and biological processes. Soil conditions, such as type, permeability, and moisture, greatly affect how land may be used, determine the potential for vegetation and habitat, and influence overland runoff that causes erosion and land slides.

On Guam, soil forms from different parent materials: volcanic rock, limestone, and bottomland/coastal deposits. The three basic types are further subdivided based on pedological characteristics into distinct varieties called soil series.

Volcanic soils are generally very shallow to deep and well drained. They dominate southern mountainous terrain and are typically found in steep settings.

Limestone soils are generally very shallow and well drained. They cover parts of northern Guam where limestone forms the land surface (and also most of the northern Guam). They are typically found in level to moderately sloping settings.

Bottomland (or strandline) soils are deep and very deep, and poorly drained. They are found in valley bottoms and coastal plains.

Soil is an integral part of a healthy terrestrial ecosystem and a truly precious resource that must be conserved. As Guam deals with a growing population and rapid urban development, issues related to soil erosion and soil and water pollution are becoming critical.


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