Yield and energy efficiency of crop rotations with sunflower at different rotation intervals under conditions of adequate moisture in the Right-Bank Forest-Steppe

Goal. To determine the effect of varying sunflower inclusion rates in crop rotations on their overall productivity and energy efficiency under conditions of sufficient moisture in the Right-Bank Forest-Steppe. Methods. Field study — to examine the effect of the crop rotation factor on crop yield formation; quantitative-weight method — to determine yield structure parameters; calculative-comparative methods — to determine the energy efficiency indicators of crop rotations; mathematical-statistical methods (analysis of variance) — to process data and assess the reliability of results using standard computer software, Microsoft Excel 2016 and Statistica 10. Results. Field studies were conducted in a long-term experiment at the Khmelnytskyi State Agricultural Experimental Station of the Institute of Feed and Agriculture of Podillia of NAAS during 2021–2023 on podzolized chornozem in five different grain-row crop rotations, with sunflower saturation ranging from 14.3% to 50%. It was found that the overall productivity of the crop rotations depended on the proportion of grain and oilseed crops, particularly sunflower. When the crop rotation was saturated with sunflower at 14.3 – 33.3%, the grain yield per hectare of crop rotation area was 3.36 – 4.46 metric tons, sunflower seed yield was 0.45 – 1.02 metric tons, and soybean yield was 0.57 – 0.85 metric tons, feed units — 5.82 – 6.80 metric tons, grain units — 5.76 – 6.36 metric tons, and digestible protein — 0.739 – 0.810 metric tons. Including sunflowers in 50% of the crop rotation resulted in a 13% decrease in grain yield per hectare of crop rotation area and a 12% decrease in feed units. The results of the energy assessment indicate a decline in efficiency indicators per hectare of crop rotation area as the share of sunflower in the crop rotation increased to 20–50%. Energy costs increased by 9–42%, while the energy efficiency coefficient decreased by 6–19%. Conclusions. Under conditions of sufficient moisture in the Right-Bank Forest-Steppe on podzolized chornozems, the most rational rotation is a 7-field rotation with 14.3% sunflower, resulting in the following yields per hectare of rotation area: grain — 3.44 metric tons, sunflower seeds — 0.45 metric tons, and soybeans — 0.85 metric tons; feed and grain units — 5.82 and 5.76 metric tons, respectively; digestible protein — 0.756 metric tons; and an energy efficiency coefficient of 3.40 conditional units.