DYNAMICS OF QUANTITATIVE AND QUALITATIVE INDICATORS OF HUMUS CONTENT IN SOIL WHEN LONG-TERM CULTIVATING WINTER RYE IN CONSTANT CROPS

The main source of nutrients and energy for all living things in the soil is organic matter, thanks to which the continuous cycle of nutrients in nature is maintained. Long-term functioning of the soil in agrosystems leads to a state of equilibrium of organic matter with an appropriate level of its stability. As a result of reducing the application of fertilizers, especially organic ones, fundamental changes have occurred in the small (biotic) cycle of substances. Every year, the negative balance of humus reaches 370–400 kg/ha, and the annual decrease in its reserves exceeds 20 million tons. According to soil survey materials, in the most fertile typical black soils of the Karlivska community of the Poltava region, the humus content currently does not exceed 6,0–6,5%, or 2,0–2,5% less than at the time of their survey by the expedition of V.V. Dokuchaev in 1890. The problem of humus is undoubtedly one of the key ones in solving the problems of stabilizing and restoring soil fertility. Long-term studies with winter rye in constant crops, which are conducted at the Poltava Agricultural Research Station, make it possible to determine and generalize its influence on the dynamics of winter rye productivity. At the same time, changes in agrochemical soil indicators are also observed. As a result of the experiment on the cultivation of winter rye in constant crops, it was found that humus content in the soil is not a statistical indicator and changes in absolute values, both in the spring and summer-autumn periods, and over the years of observation. Statistical analysis of the data obtained during the studies showed a direct and inverse correlation between the humus content indicators and the hydrothermal conditions during the research. It is proposed to widely use the results of the studies in solving fundamental issues of agriculture, in deep complex studies, and for the demonstration of the role of the main factors and conditions of plant life.