The potassium status of arable soils in European Russia

The problem of potassium supply in soils of European Russia has been studie d with allowance for their genesis, content, composition, and crystallochem ical features of clay minerals, as well as physicochemical and other proper ties responsible for the potassium behavior in the soil. The criteria based on the degree of the soil exchange complex saturation with potassium and t he potassium content in 0.01 M CaCl2 were substantiated, and the parameters of optimal, moderate, and low potassium supplies of soil were presented.