HE YIELD AND PRODUCTIVITY OF SUNFLOWER DEPEND ON ITS SHARE IN CROP ROTATION

Abstract

The importance of sunflower as the main oilseed crop, high economic efficiency, saturation of the agricultural market with high-quality seeds of modern hybrids resistant to adverse environmental conditions, diseases, and pests with high yield potential con tribute to increasing the share of the crop in crop rotations. Despite many researchers not recommending returning sunflower to the crop rotation earlier than five to eight years, growing sunflower after sunflower is possible. One of the main conditions for obtaining a high yield in continuous sunflower crops is the nutrient background. Research was conducted on alternating sunflower and maize for grain in a two-field crop rotation and for sunflower cultivation in monoculture under different fertilization systems in the fields of the Institute of Steppe Agriculture of the National Academy of Sciences. Annual alternation in the crop rotation of sunflower and maize contributed to an increase in sunflower yield to 1.75 t/ha compared to its continuous cultivation, where the yield did not exceed 1.39 t/ha; the yield increase due to the crop rotation factor was 0.36 t/ha or 21.5%. The fertilization system significantly affected the yield of sunflower. The highest yield was achieved with the organo-mineral fertilization system in a crop rotation with 50% saturation with sunflower at 2.33 t/ha. Moreover, the application of mineral fertilizers together with sunflower residues in monoculture neutralized the effect of the crop rotation factor and provided a seed yield at the level of crop rotation with alternating crops, 0.71 t/ha. The highest yield increase was obtained with the mineral fertilization system, 0.51 t/ha or 36.7%; for the organo-mineral sys tem, the yield increase was slightly lower at 0.46 t/ha or 27.4%. Higher productivity was formed by sunflower crops in a crop rotation with 50% saturation with crops. The crop rotations factor ensured an increase in grain units, feed units, and digestible protein to 3.51 t/ha, 1.93 t/ha, and 0.66 t/ha, respectively; the yield increase compared to sunflower monoculture was 0.72 t/ha, 0.39 t/ha, and 0.14 t/ha. The increase in sunflower productivity due to the fertilization system factor was even more significant, and under the organo-mineral system in a crop rotation with 50% saturation with sunflower, they were the highest at 4.67 t/ha of grain units, 2.57 t/ha of feed units, and 0.89 t/ha of digestible protein.