Influence of conditions of mineral nutrition, clean and occupied fallows on the fertility of the chestnut soil of the Eastern Ciscaucasia

In conditions of a shortage manure and high prices for mineral fertilizers, the preservation improvement soil fertility is an urgent problem agriculture. The studies were carried out at Prikumsk experimental selection station in two 6-field crop rotations from 1969 to 2019 purpose research study, long­ term stationary experiment on various nutritional backgrounds, effect grain with clean busy fallow chestnut arid zone Stavropol Territory. grain-and-row rotation 16.6% pure fallow, decrease humus content control was 0.10%, reserves 2.6 t/ha, against fertilized background — 0.09%, 2.3 occupied contrary, it increased by t/ha 0.11%, 2.8 t/ha. mobile phosphorus topsoil 1.7 mg/kg, stocks 4.3 kg/ha, 3.4 mg/kg 8.7 variant 7.5 19.1 kg/ha 7.4 18.9 kg/ha. exchangeable potassium 3 46 8 115 they 4.2-4.1 times lower control, 13.7-13.0 background, compared fallow. application fertilizers contributed 3.7 times, 3.5 only 12.2 10.6%. Sainfoin significantly reduced its consumption variant.