BIOLOGICALAND METHODS OF ENHANCING SOIL FERTILITY IN ORGANIC AGRICULTURE IN THE LOWER VOLGA REGION
A comparative assessment of the predecessors and methods of biologization in the cultivation of winter wheat, grain sorghum and oats in the steppe zone of the chestnut subzone of light chestnut soils of the Lower Volga region is given. It has been established that the highest positive balance of organic matter is ensured in winter rye for green manure when growing over oats in a four-field biologized crop rotation, where its green mass is buried in the soil - +5.54 t/ha. The high balance of organic matter is observed in grain sorghum: when grown for winter wheat, crop and root residues and straw that enter the soil in a six-field crop rotation is +3.48 t/ha, according to the same predecessor, but in a four-field crop rotation - +3, 36 t/ha and in peas, where its crop and root residues and straw in the eight-field crop rotation return to the soil - 3.41 t/ha. Sorghum was the most productive crop in the cultivation of winter wheat in the four-field crop rotation, where straw and crop residues returned to the soil - 2.82 t/ha. The highest yield of winter wheat is provided in the control variant, where it is grown for a black pair - 2.69 t/ha and for cultivation in a four-field crop rotation using a sidereal pair with winter rye - 2.68 t/ha