BIOLOGICAL PRODUCTS AS A MEANS OF RESTORATION OF BLACK SOIL HEALTH

Usage of crop residues as fertilizer leads to soil intoxication and, consequently, to soil health deterioration. Usage of beneficial microorganisms solves this problem. The studies were carried out in 2018-2021 in order to study the effect of Gribofit and Imunazot microbiological products, nitrogen fertilizers, individually and in combination, on phytotoxic effect removal of the soil when plant residues are applied for fertilization in grain crop rotation on typical slightly eroded heavy loamy black soil. The experimental field is located in Kursk region, Medvenskiy district of Panino village. All residues were used for fertilization in all variants of the experiment; nitrogen fertilizers were additionally applied at a dose of 10 kg of a.r. N per 1 ton of straw in the second variant; in the third variant, seeds, soil, crops and straw residues were inoculated with biological products Gribofit and Imunazot; in the fourth variant, combined application of nitrogen fertilizers and biological products as studied. Specification of soil phytotoxicity was carried out according to international standard ISO 11269-2:2012, as a test culture, seeds of radish (Raphanus sativus L.) were used. Application of plant residues for fertilization for four years led to sustainable phytotoxic effect of the soil, reducing seed germination energy of the test crop from 88% to 57%. Usage of Gribofit and Imunazot separately and in combination with nitrogen fertilizers contributes not only to improvement of soil ecological state, but also to its health. Biological products increase seed germination energy of the test culture from 11% to 28% compared to absolute control, depending on the type of plant residues, and index of the assessed factor increases to 1.27. Application of nitrogen fertilizers with cereal straw contributed to low toxicity of class 4. Broad beans have the ability to reduce soil toxicity, but their effect lasts only during the period of crop cultivation.