Restoration of fertility of unproductive sod-podzolic soils re-introduced into agricultural circulation

The purpose of research is to develop agro-reclamation measures to restore the fertility of low-productive sod-podzolic sandy loam soils for the conditions of the southern part of the Non-Chernozem Zone of Russia. Objectives: to conduct a comparative assessment of the impact of granular fertilizer based on turkey droppings and a liquid-phase biological product (LPBP) on increasing soil fertility, phenological characteristics of plants, crop yields and their quality. Six variants of the field experiment were developed: control variant (without fertilizers); granular fertilizer based on turkey droppings at a dose of 15 t/ha; granular fertilizer based on turkey manure at a dose of 15 t/ha together with pre-sowing seed treatment with 1 % LPBP; pre-sowing seed treatment with 1 % LPBP; granular fertilizer based on turkey droppings at a dose of 30 t/ha. The application of organic ameliorant and pre-sowing treatment of seeds with a biological pre¬paration help to improve the agrochemical parameters of the soil, and, as a result, a higher yield of perennial grasses. The best option is option G30, where the yield was 48.3 t/ha of green mass of grass in total for 2 cuttings, which is 33.8 % more than the control option. In the G15 and G15 LPBP options, the harvest was practically not inferior and exceeded the control option by 30.5 and 24.4 %, respectively, soil fertility indicators improved: soil acidity decreased to 4.8–5.0 (pHsol) and 5.4–5.6 (pHwod), an increase in organic matter by 33.9 %, the content of mobile phosphorus and mobile potassium, and the concentration of total nitrogen increased significantly.