Yevtushenko T. Restoration of the Fertility of Chernozems Typical of the Forest-Steppe of Ukraine Under Soil Conservation Technologies

The dissertation describes the results of a comprehensive study of the agrophysical, physico-chemical, water-physical and agrochemical properties of chernozems typical of the Forest-Steppe of Ukraine, the level of productivity and economic efficiency of agricultural crops in short-term crop rotation using of soil conservation technologies, deep cultivation, fertilizers and a time factor. A theoretical justification and an experimental solution to the problem of restoring soil fertility are given. The results obtained and the generalization of the material make possible to assert that for optimizing of indicators of soil bulk density, porosity and moisture accumulation, the transition to soil cultivation without moldboard and the use of minimization elements should begin with the elimination of the “plow hardpan”, namely the use of different-depth non-plowing cultivation with periodic deep loosening, after 14 years of using of soil conservation technologies, it is possible to use shallow cultivation for winter wheat growing. Long-term use (14 years) of non-plowing cultivations with an organo-mineral fertilizer system including straw and green manure increases the organic matter content on 0.36-0.46 % in 0-30 cm soil layer of chernozem typical of the Right-Bank Forest-Steppe compared to the non-fertilized variant. In the 0-30 cm soil layer under non-plowing treatments, the humus content was higher on 0.06-0.08 % compared with variant under plowing, and humus storage rates were higher on 2.0-4.0 t/ha accordingly. In the 3rd year of using of different systems of cultivating of chernozem typical of the Left-Bank Forest-Steppe, significant changes are visible only in the 0-10 cm layer, where when using non-plowing treatments with the use of organicmineral fertilizers, the humus content increased by 0.08-0.10 %. Crop fertilization systems had a greater impact on the content of nutrients in chernozem typical compared to tillage systems. There is a close correlation between soil fertility indicators (soil bulk density, moisture reserves, humus content and available forms of nutrients) and yield of corn for grain, and the dynamics of soil bulk density in chernozem typical during the growing season did not significantly affect the yield of winter wheat and spring barley. The use of mineral fertilizers on with straw background contributed to an increase in crop rotation productivity by 47-53 %; with straw and green manure - by 73-78 % compared with the variant without fertilizers. The highest crop rotation productivity in the Right-Bank Forest-Steppe was obtained with the use of straw (1.2 t/ha), siderate, N12 and N78P68K68 with deep non-plowing cultivation (6.71 t/ha), under conditions of the Left-Bank Forest-Steppe with the use of straw (1.2 t/ha), N12 and N95P75K75 under different-depth non-plowing cultivation with deep cultivation up to 50 cm (7.37 t/ha).