Fertility state of leached chornozem with long-term use of fertilizers in beet-crop rotations

Abstract

Goal. To determine the content of humus and nutrients in leached chornozem during the long-term use of different fertilizer systems in beet-crop rotations. Methods. Field — to determine the effect of fertilizer systems and crop rotation on the content of humus, mobile phosphorus, and potassium in leached chornozem; variance analysis using the Statistica computer program, 2010. Results. Data from studies of 50 years of application of various fertilizer systems in beet-crop rotations are presented and their influence on the fertility of leached chornozem is established. It was found that the high content of humus and nutrients in the soil was formed under organo-mineral fertilizer systems, and the application of mineral fertilizers increased the mineralization of humus. It was established that in the grass-field crop rotation, fertilizers formed higher soil fertility than in the inter-row and inter-row-grain rotations. Conclusions. During the application of N53P42K42 + 6.7 t of manure per 1 ha of arable land for 50 years, the humus content in the soil was 3.44%, N53P42K42 + by-products — 3.30%, which was higher than the control without fertilizers by 0.37 and 0.23%, respectively. In inter-row and inter-row-grain rotations, the humus content was lower by 0.22–0.37% and 0.14–0.23%, respectively. With the use of only mineral fertilizers, the mineralization of humus increased and its content decreased compared to the control without fertilizers in crop rotations by 0.05–0.09%. Long-term application of phosphorus fertilizers at a dose of 42 kg/ha of arable land formed a high supply of leached chornozem with mobile phosphorus. The highest content of mobile phosphorus in the soil was when N53P42K42 + 6.7 tons of manure was applied per 1 ha of arable land: in layers 0–30 cm — 290–301, 30–40 cm — 218–247 mg/kg of soil. The content of mobile phosphorus in the row crop rotation compared to its content in the crop rotation and grain-row crop rotations was higher by 7 and 11 mg/kg of soil. The use of potash fertilizers at a dose of 42 kg/ha of arable land formed the average soil supply of mobile potassium — 80–96 mg / kg of soil. With additional input of potassium in manure (40 kg / ha) and by-products, the content of mobile potassium in the soil increased: when using N53P42K42 + 6.7 t of manure per 1 ha of arable land, it was 127–145 mg/kg, N53P42K42 + by-products — 103–123 mg/kg of soil. The content of mobile potassium in the grain-row crop rotation compared to its content in the crop rotation and row crop rotation was higher by 11 and 18 mg/kg of soil.