The results of 9 years (from 2007-2016) re-search are presented in the study. The research was performed at the premises of Tuvinian Agricul-tural Research Institute considered with the proce-dure of field trial. In order to develop crop cultiva-tion technology in the field of crop rotation we stud-ied the impact of spring wheat forecropes on the elements of dark brown soil effective fertility such as density, soil porosity, productive moistness stock, dynamics of nitrate nitrogen and liable phos-phorus and its impact on dark brown soil productivi-ty. For the first time biological methods of enhanc-ing soil fertility and yield of obtaining an environ-mental friendly products, energy saving technolo-gies and techniques, high-yielding crop for farms of different ownership forms were used. The closest to optimal conditions for the growth and development of spring wheat in the field of crop rotations were demonstrated by such forecropes as melilot and pea (green manured). Agrophysical indicators of density decreased compared to initial indicators on 0.08 g/c3 for all crops and increased on 0.05 g/c3 for the complete fallow. Productive moisture was 49 % and 45 % from the amount of precipitation in the period between autumn and spring tests after green-matured and seeded fallows consequently. Meter-deep layer of complete fallow’s soil in-creased at 23 %. Nitrate nitrogen concentration af-ter green manured crops (melilot, pea) changed from high (20.5 mg/kg) to medium (18 mg/kg). The whole green manure forecrop plowing increased the purification of soil and wheat plantings from weeds by 10-20 % in comparison with just stubble and roots plowing. Average spring wheat produc-tivity varied between 2.0 to 2.1 tons\hectare during the years of study.
forecrop, pure bare fallow, sideral, seeded, dark chestnut soil, density, productive moisture, nitrate nitrogen, spring wheat, yield
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