Soil Degradation

a process that results in the partial loss by soil of previously accumulated organic matter, exchangeable alkaline-earth cations, and the clayey fraction. This term previously designated the podzolization of chernozems under the influence of forest vegetation. Thus the term podzolized chernozems is now used in soil classifications instead of the former term degraded chernozems. In the initial stage, soil degradation occurs in the lower part of the humus horizon and in the illuvial carbonate horizon (under the humus horizon). Degradation in the lower and sometimes middle sections of the humus horizon results in so-called siliceous sprinklings, consisting of quartz and feldspar grains, weak base unsaturation, some accumulation of silica, a decrease in sesquioxides (compared to the parent rock), and other signs of weak podzolization. These phenomena, how-ever, do not bring about a marked decrease in soil fertility. Degraded, or podzolized, chernozems are as fertile as typical chernozems.