Chemical, mineralogical and quantification of nutrient distribution of the three geological forest soils in Okinawa Island

Abstract

The chemical and mineralogical compositions were studied to quantify and compare the nutrient disribution for the three geological forest soils (limestone, marlstone and silicate rocks). Three sampling poits were established for each soil type in which samples were taken from surface (0-10 cm) and subsurface (10-20 cm).The mineralogy of clay fractions at all three sites was dominated by kaolinite and illite, while quartz was a dominant in the silt fractions. All soil samples from silicate rock were strongly acidic with pH ranged from 3.6 to 5.6, while that from limestone and marlstone sites were typically neutral to slightly alkaline.In generally,limestone soil is much enriced with nutrints as compared to marlstone and silicate rocks.