The effect of permanent fallow on the chemical and physico-chemical properties of typical chernozem

The article studies the effect of permanent fallow on the chemical and physico-chemical properties of typical chernozem of the Kursk region (Haplic Chernozem, Loamic, Pachic). During 74 years of permanent fallowing, the properties of typical chernozem have undergone significant changes. The amount of organic carbon decreased by 45% compared to its content in virgin chernozem, from 5.07% to 2.7%. The annual mineralization loss of organic carbon was approximately 0.03% per year. The amount of total nitrogen decreased by 49% of its content in virgin chernozem, from 0.45% to 0.23%. Nitrogen losses were approximately 0.003% per year. The content of mobile phosphorus in the permanent fallow variant increased from 63.0 mg/kg of soil to 149.5 mg/kg due to the transition of organophosphates into mineral forms. Cation exchange capacity has changed from 49.52 mg-eq/100 g of soil in the virgin chernozem to 36.71 mg-eq/100 g of soil. The value of hydrolytic acidity decreased by 1.05 mg-eq/100 g of soil, and the total exchangeable bases by 11.98 mg-eq/100 g of soil. Keywords: TYPICAL CHERNOZEM, PERMANENT FALLOW, ORGANIC CARBON, PHYSICO-CHEMICAL PROPERTIES OF CHERNOZEM, TOTAL NITROGEN, PHOSPHORUS, POTASSIUM