The article presents the results of research conducted during 2016-2019 on the impact of different rates of mineral fertilizers and by-products of the predecessor on the content of chemical nutrients in plants and the yield of maize hybrids in the Forest-Steppe. The aim of the research was to establish the peculiarities of nitrogen, phosphorus and potassium accumulation in maize plants in ontogenesis in relation to the yield of hybrids of early and middle-early maturity groups to optimize the mineral nutrition of the crop. The research was conducted on dark gray wooded soil using field, chemical, calculation-weight and mathematical-statistical methods. According to the stages of growth and development of BBCH, the peculiarities of the dynamics of nitrogen, phosphorus and potassium content in plants of hybrids with FAO 190 and 280 depending on the agrochemical load of growing technology are established. Varietal regularities of concentration of chemical elements in maize plants in connection with the accumulation of dry matter by crops in ontogenesis and yield were revealed. Hybrids with the corresponding genetically determined level of nitrogen, phosphorus and potassium content in plants have been identified and its influence on the realization of genotype productivity potential has been shown. The decisive role of potassium and nitrogen in the formation of the corn crop on dark gray wooded soil has been experimentally proved and confirmed on the basis of statistical and correlation analyzes. All hybrids were characterized by high tightness of correlations between yield and content in plants of nitrogen (r = 0.760–0.934) and potassium (r = 0.755–0.943) during the growing season as opposed to phosphorus, where these connections were of medium strength (r = 0.334–0.589) and only partially close (r = 0.702–0.806). According to the results of plant diagnostics of mineral nutrition of plants, the most effective growing technologies with different agrochemical loading are singled out, which ensure the yield of early and middle-early maize hybrids in agro-climatic conditions of the Forest-Steppe at 9.56–10.39 and 11.21–12.10 t/ha.