PATTERNS OF SOIL PROCESSES ON DARK CHESTNUT SOIL UNDER CONDITIONS OF ITS USE IN THE CONDITIONS OF THE STEPPE OF UKRAINE

As a result of four-year research, the patterns of soil processes development depending on the parameters of reclamation load were established. It was established that at the end of vegetation season irrigation of crops with water with high mineralization leads to deterioration of soil structure, where the largest amount of aggregates >10 mm (42.67%) was observed during disk tillage (a similar trend was observed for aggregates <0.25 mm). On average, during 2016-2019, under the influence of irrigation, the transformation of the ionic composition of the aqueous extract led to a change in the chemistry of salinity from sodium chloride-sulfate to calcium-sodium sulfate in all variants, regardless of the studied factors. The most favorable conditions for the formation of the yield in the experiment were created under a differentiated system of tillage with one split for crop rotation and with the introduction of increased doses of fertilizers, which per 1 ha of crop rotation area provided the highest productivity, which was for corn 15.49 t/ha, sorghum - 8.72 t/ha, wheat winter - 7.07 t/ha, and only for soybeans the best conditions this year were created for 1 option - 4.27 t/ha. The highest level of profitability from 1 ha of crop rotation area was obtained for the average fertilization background 2 (N120P52,5 ) for differentiated tillage - 199%, while for other tillage systems and fertilizer doses it decreased to 33-189%.