Ivanina R. Reproduction the fertility of leached black soil and crop productivity in grain-beet rotations in the Right-Bank Forest-Steppe of Ukraine.

Actuality of theme. Information obtained in long-term stationary experiments on the impact of 40 years of fertilization on the fertility of leached black soil and crop yields, supplemented by innovative solutions on optimize the use of nitrogen fertilizers for winter wheat allows to develop a fertilizer system based on the principles of sustainability and innovation that is why it is timely and relevant. Scientific novelty of the obtained results. For the first time in the conditions of the Right-Bank Forest-Steppe of Ukraine in crop rotation with bean grasses and rotation with grain and row crops regularities of change the fertility of leached black soil after 40-year application of fertilizers are established. It was proved that the process of reproducing the fertility of leached black soil is determined by the application of organic fertilizers, the dose of mineral fertilizers and the introduction of perennial legumes in crop rotation. It was improved the system of winter wheat fertilization through optimizing doses and ways of nitrogen fertilizer application. It was further developed the issues of nitrogen nutrition efficiency in achieving high yield and grain quality of winter wheat; questions of predecessors in moisture supply of winter wheat plants and their influence on microbial soil cenosis. The practical significance of the obtained results. According to the temporary field experiment and their production inspection, a system of effective application of nitrogen fertilizers for winter wheat has been developed, which provides grain yield over 7 t/ha with a profit from fertilizer over 9000 UAH/ha. The main results of research. It is established that the expanded reproduction of humus content in leached black soil was achieved in crop rotation with bean grasses after 40-year application of N43R43K43 + 8.3 tons of manure per 1 ha of arable land: humus content in the layer 0-30 cm - 3.52%, 30-40 cm - 3.28% with excess of the control without fertilizers - by 0.36% and 0.22%. It was investigated that the annual application of 64 kg of phosphorus with organic and mineral fertilizers per one ha of arable land provided expanded reproduction of the mobile phosphate fund in the leached black soil of both crop rotations: the content of mobile phosphorus in the layer of 0-30 cm was 309-323 mg/kg, 30-40 cm - 229-266 with excess of the control without fertilizers - by 133-138 and 75-103 mg/kg of soil. According to the results of long-term field studies, it was found that the organic-mineral fertilizer system formed the stability of the mobile potassium fund in the leached black soil of both crop rotations at the average level of provision: in the layer 0-30 cm was 102-104, 30-40 cm - 79-89 mg/kg. It was found that largest number of soil microorganisms in the phase of spring tillering of winter wheat of both grain chains in crop rotation was observed at doses of N60R60K60 against the background of 40-year application of N43R43K43 + 8.3 tons of manure per 1 ha of arable land - 42.2-45.6 million CFU in 1 g of absolutely dry soil. It was investigated that the application of fertilizers significantly reduced the abundance of weeds in the agrocenosis of winter wheat in both grain chains of crop rotation. It was found that in crop chain with clover the grain yield of winter wheat was higher than after the predecessor of spring vetch by 0.38-1.32 t/ha, the protein content in the grain by 0.3-0.4%. The highest grain yield in chain with clover was achieved with the application of N60P60K60 - 6.76 t/ha with an advantage to the control without fertilizers - 1.99 t/ha. The increase in yield and grain quality of winter wheat was facilitated by triple applications of nitrogen fertilizers of total dose of 110 kg/ha, which included 60 kg/ha of nitrogen on the frozen soil surface in early spring in the form of ammonium nitrate and two foliar fertilization with urea solutions at the phase BBCH 31-32 with nitrogen dose of 30 kg/ha and BBCH 75-77 at a dose of 20 kg/ha: grain yield - 6.90 t/ha, protein content - 12.5%. According to the results of long-term field studies, it was found that the spring barley in both crop rotation chains, and clover responded well to the aftereffect of fertilizers application with increased yields - by 0.82-1.04 and 14.7-16.0 t/ha, respectively, while spring vetch insignificantly reacted to the aftereffect of fertilizers. It was determined that the highest productivity of grain chain has been achieved in crop rotation with bean grasses when applied for 40-ty years of N43R43K43 + 8.3 tons of manure and N43R43K43 + by-products per 1 ha of field: harvest of feed units of 8.02 and 8.17 t/ha, grain harvest of 3,33 and 3.35 t/ha of chain. It was investigated that most energy and economically efficient was the cultivation of crops in chain with clover when applying N20P20K20 + straw per 1 ha of rotation chain: Kee – 6.3, absolute profit – 44249 UAH/ha, profitability – 104%.