INFLUENCE OF AGROCHEMICAL LOAD ON PLANT SUPPLY OF FOOD ELEMENTS AND YIELD OF MAIZE IN THE FOREST-STEPPE

The article presents the results of research on the optimization of the supply of maize plants with the main nutrients under different agrochemical loads in the Forest-Steppe. The aim of the research was to establish the effect of different doses of mineral fertilizers and by-products of the predecessor as fertilizers on the supply of plants with nitrogen, phosphorus and potassium and corn yield. The research was carried out during 2016-2019 on dark gray wooded soil of the Forest-Steppe with the use of field, chemical, calculation-weight and mathematical-statistical methods. It were found that long-term growing of agricultural crops for 30 years under different agrochemical loading in crop rotation on dark gray wooded soil of the Forest-Steppe led to the creation of different agrochemical backgrounds. According to the results of soil and plant diagnostics, it has been established that nitrogen is the limiting nutrient for growing corn. In the variants with application of increased (N180P120K180) and high (N240P120K240) norms of mineral fertilizers against the background of by-products of the predecessor (winter wheat straw), where the highest yield of corn is formed - 11.21-12.10 t / ha, mobile phosphorus content 20 cm layer of soil was very high, mobile potassium - high, easily hydrolyzed nitrogen - very low. In these variants, maize plants in stages BBCH 16, 19 and 65 accumulated the optimal amount of nitrogen, and the content of phosphorus and potassium showed optimal and high supply during the growing season for the application of mineral fertilizers in the norms above N60P45K60.According to the results of correlation and regression analysis, the decisive role of nitrogen and potassium in the formation of corn productivity was confirmed. Mathematical models have been constructed that make it possible to predict the level of maize yield depending on the content of chemical elements in the soil and plants at the early stages of BBCH development.