AGROCHEMICAL EVALUATION OF THE EFFICACY OF BIOPREPARATIONS IN A HIGHLY CROP ROTATION

Objective. Determine the parameters of uptake of organic matter and biogenic elements withby-products of crops under the use of mineral and green-manure-mineral fertilization systems andmicrobial preparations. Methods. Field experiment, agrochemical, balance, statistical. Results.Under the conditions of short crop rotation “winter wheat – intermediate green manure – corn forgrain – soybean – winter wheat”, the influence of microbial preparations Biogran (on the basis ofnitrogen-fixing bacterium Azospirillum brasilense 410 and physiologically active substances) forcorn and Nitro-Legu (on the basis of complex of diazotrophs Bradyrhizobium japonicum, Azospirillum brasilense and polysaccharide) for soybeans on crop yields, uptake of by-products in the soil,balance of nitrogen, phosphorus and potassium depending on fertilization systems. Under exposureto biopreparations, uptake of corn by-product in the soil increased by 1.41–2.12 t/ha, soybeans —by 0.51–0.71 t/ha of dry matter, depending on the agrarian backgrounds, which, taking into account the humification factors, can provide soil replenishment with humus at the level of 0.31 to0.47 t/ha and 0.12–0.17 t/ha, respectively. Nitrogen and phosphorus balances, as well as their intensity under the mineral fertilization system were positive. Green-manure-mineral fertilization system and pre-sowing bacterization of seeds helped to improve the parameters compared to the mineral fertilization system. Potassium balance was slightly deficient (–16.2 to 20.4 kg/ha at a balanceintensity of 78–80 %) under exposure to the mineral fertilization system and positive under exposure to green-manure-mineral system. Microbial preparations helped to improve parameters. Additional uptake of the biogenic element compounds in the soil provided an increase in the yield ofwinter wheat. According to the results of the evaluation of the balance of the key nutrients, a satisfactory ecological balance was created in the short crop rotation under exposure to green-manuremineral fertilization system and pre-sowing bacterization of corn and soybean seeds. Conclusion. Upon evaluation of the efficacy of microbial preparations in crop cultivation technologies, theparameters of uptake of organic matter and biogenic element compounds with by-products in the arable soil layer should be taken into account along with their direct effect on yield formation andproduct quality.