Effectiveness of short-term crop rotations under different fertilization systems in the insufficient moisture zone of the Right-Bank Steppe of Ukraine

Topicality. In the condition of insufficient moisture in the Right Bank Steppe of Ukraine, agriculture is associated with weather risks, non-compliance with the appropriate structure of sown areas and fertilization systems, which makes it difficult to obtain high and stable yields of agricultural crops. The development of agricultural systems is the basis for increasing both yield levels and the competitiveness of the agricultural industry as a whole. Aim. To study the influence of fertilization systems on the fertility of ordinary chernozems and crop productivity in biological short-term crop rotations. Methods. Field trial, laboratory, statistical methods. Results. It was found that the field crops of both grain-fallow-row and grain-row crop rotations were formed the highest productivity under high level of fertilization. Under different fertilization systems, it was noted that the productivity of grain-fallow-row crop rotation is higher than grain-row crop rotation by 8.3 t/ha or by 5.6 %. The productivity of both crop rotations was increased by an average of 6.4–7.8 % due to the application of microbial preparations against the background of mineral and organomineral fertilization systems. The content of mobile phosphorus and exchangeable potassium in all variants of both crop rotations increased due to studied fertilizer rates, but these rates were insufficient to maintain the content of nitrogen and humus at the initial level. In both crop rotations, it was noted that the lowest degree of "burning" humus was on the background of the organomineral fertilizers. When organomineral fertilizers were applied in the grain-fallow-row crop rotation, this indicator was 0.50 % that was 0.06 % less compared to variant with the mineral fertilization and control, and in grain-row crop rotation, this indicator was 0.46 % that was less by 0.11 and 0.06 %, respectively. Conclusions. Profit at the level (on average) of UAH 9114.4/ha was obtained in grain-fallow-row crop rotation, it is more by UAH 1039/ha, or 11.4 % compared to grain-row crop rotation. The advantage was that the predecessor residues in the organomineral fertilizer system was used as organic fertilizer, which have a positive effect on the synthesis of organic matter in the soil, productivity and economic efficiency. Keywords: crop rotations, fertilizers, yield, productivity, soil fertility, economic efficiency.