Characterization of a Buried Latosol from Northern Puerto Rico

Abstract

Data on the morphological, physical, and chemical properties of a buried soil profile in northern Puerto Rico are presented. The solum is of a distinct red color some 42 inches in depth, grading into a brownish-yellow unaggregated sandstone of marine origin and containing numerous iron concretions. The soil is a loamy sand corresponding rather closely to the Islote soil, a somewhat extensive soil in northern Puerto Rico. The relatively high water retention at pF 4.2 in comparison to that retained at pF 2.7 indicates the probable droughtiness of this soil, a feature of most latosols in Puerto Rico. The rather relatively low fertility status—low exchange capacity, organic matter, and nitrogen—is also characteristic of latosols. The alkalinity throughout the profile may partly be the result of lime leaching over a period of years from the overlying 18- to 25-foot layer of highly calcareous sandstone. The weight of this sandstone layer can also account for the compaction of the solum. The over-all picture indicates that laterization was an active process in past geologic time, such as in the Pleistocene epoch when this soil was probably developed.