Soils of High-Rainfall Areas in the Hawaiian Islands

Rainfall in the agricultural areas of the Hawaiian Islands covers the extremely wide range of from less than 20 inches to more than 200 inches annually. A generally open condition of the soil permits comparatively rapid penetration of water, so that even in areas of high rainfall there is little runoff except during the heavier storms. The soils in the more humid regions are therefore subject to intense leaching. If satisfactory crops are to be produced indefinitely under conditions of high rainfall, it would seem appropriate to inquire into such matters as the levels of exchangeable bases in the soils, the reserves of potentially exchangeable bases, the acidity of the soils (pH), the additional acidity that could develop from further depletion of the bases, the capacities of the soils to retain added bases, and the materials responsible for these capacities. Such knowledge of the chemical characteristics of the humid-region soils should aid in the determination of those agricultural practices that will insure continued productivity