Chemical Properties of Forest Soils

Abstract

In soil, there are inorganic and organic solids, solutes, liquids, and gases. There are larger and smaller particles, including sand, silt, and clay, and colloids—fine crystalline minerals and amorphous humus. Fine silicate clays and oxides and hydroxides of iron and aluminum, lime, gypsum, and phosphates are there along with hundreds of many other compounds, and nutrient ions. These materials are variably active and reactive; some are almost inert such as the sand grains, and some undergo continuous dynamic reactions such as the colloidal and charged clay particles. Insoluble materials are made soluble, and soluble materials are insolubilized by diverse chemical and biochemical reactions. Important indices of the chemical behavior of all soils, including forest soils, are pH, cation-exchange capacity (CEC), anion-exchange capacity (AEC), base saturation (BS) percentage, exchangeable sodium percentage (ESP), electrical conductivity, and redox potential. These indices characterize the forest soils and affect the growth and distribution of forest tree species.