АГРОГЕННАЯ ЭВОЛЮЦИЯ ФРАКЦИОННОГО СОСТАВА КАЛИЯ ТОРФЯНЫХ ПОЧВ ПОЛЕСЬЯ

The article describes how drainage and long-term (50 yeas) agricultural use of peat soils causes transformation in composition, structure and reserve of potassium fractions. In peat-bog soils reserve of gross forms of potassium in 0-40 cm layer is 560 kg/ha, exchangeable peat forms - 100 kg/ha. In agro peat soils of different stages of evolution gross peat form increases in 2.5-4.9 times, moving fractions and others increase in 5-10 times or more. In organic mineral soils with organic matter less than 20 % all fractions decrease. The lowest reserves of peat fraction are in mineral post-peat soil (exchangeable, moving, and available forms are 0.5-0.52 t/ha and water-soluble form is 0.14 t/ha.