Aspects of Soil Toxicity in the Castac Lake Region of California

Abstract

Geographers recognize that soil quality is one of the most criti cal factors influencing man's use of the land, but the objective evaluation of that quality has proven to be a very difficult problem to solve. With the possible exception of the recent 7th Approxima tion, Soil Classification,1 existing schemes of soil mapping and classi fication are generally difficult to utilize because they tend to be based on criteria which do not directly reflect the critical elements of soil quality. An attempt was made in this study to fill this void partially by analyzing certain soil properties which diminish soil quality. Therefore, this investigation focused on a set of soil proper ties associated with soil toxicity in a portion of Southern California. Inasmuch as soil fertility and toxicity are functions of the physi cal, chemical, and biological properties of soil, a rational approach to the study of soil toxicity would be to study the spatial variations of soil toxins in relation to the spatial distribution of other soil proper ties and factors influencing the soil environment. The major empha sis of this study is the nature of the areal distribution of soil boron, sodium, chlorine, zinc, and sulfate content—substances occurring in quantities which create various forms of soil toxicity in the Castac Lake Area.2