Exit of starch and bioethanol from corn crops depending on predecessors and basic tillage

Goal. To develop the basic parameters of bioadaptive technology of corn cultivation (ZEA Mays L.), and to determine the yield and quality of grain in the Steppe of Ukraine. Methods. The main — field experiment, additional — laboratory, calculation, and mathematical statistics (variance and correlation analyses). Results. The research was conducted in the conditions of the Northern Steppe of Ukraine during 2010–2024. The use of soybeans as a predecessor had a positive effect on corn grain yield (6.56–7.15 t/ha), which was much higher than after other predecessors. The lowest yield for plowing was after sunflower — 6.29 t/ha. The minimization of soil tillage after all predecessors led to a reliable harvest, which was 0.59–2.55 t/ha for direct sowing. At the same time, the harvest of corn grain for direct sowing after soybean was higher than for plowing after sunflower. Starch content in corn grain had an inverse dependence on yield (r = –0.74) and was larger than for sowing after sunflower (71.67–72.33%), and the smallest — after soybean (70.63–71.47% ). The starch content in the grain was affected by the depth of soil cultivation and had an inverse correlation (r = –0.59). With the minimization of the basic tillage, there was a general tendency to reduce the biometric indicators of the cobs, the amount of grains, and the weight of grain with 1 cob. The inverse relationship between the indicators of the crop structure and the starch content in corn grain was established (r = –0,51…–0.73). With shallow tillage, the content of starch in grain was less than in variants without soil tillage by 0.06–0.67%, and with deep plowing — by 0.57–0.97%. At the same time, it was during deep plowing that the highest yield of starch and bio-ethanol was obtained from a unit area as a complex estimated indicator of crop productivity — 4,51–5.05 t/ha and 288.2–322.7 dal/ha (2.92–3,27 thousand l/ha) respectively. For shallow soil tillage, these figures were less by 4.1–6.8%, for direct sowing — by 7.1–37.4%. The output of starch and bio-ethanol for corn sowing after soybean was higher than for plowing after sunflower and in repeated crops. Conclusions. To form a stable productivity of crops and high yield of starch and bioethanol in the conditions of the Northern Steppe, corn for grain should be grown after the best predecessors against the background of plowing as the main cultivation of ordinary black soil. Minimizing soil tillage leads to a significant decrease in the share of the potential of corn crops. Soybeans are the best precursor, after which even without tillage, corn productivity indicators are higher than after sunflower on the background of plowing.