The Environment–Forming Role of Perennial Grasses in Agriculture of the Forest-Steppe of Western Siberia

Results of field experiments in crop rotations of different specialization are presentedcereals-fallow and cereals-grasses rotations.The influence of various forecrops (fallow, Alfalfa) on individual indicators of soil fertility has been established.Negative nitrogen balance of -28 kg/ha was revealed with its intensity of 66% in a cereals-fallow rotation.The inclusion of perennial legumes, including alfalfa, provides a positive nitrogen balance in the crop rotation -21 kg/ha without additional fertilizer with a deficiency of its intensity of 119%.Under such conditions, the content of nitrate nitrogen in soil, before sowing the wheat after plowing the bean component was high, as well as after fallowing, provides an increase in the yield of spring soft wheat by 5,0 kg/ha compared to wheat.Studies were conducted in similar conditions on irrigated meadow-chernozem soil in an eightfield stationary cereals-grasses crop rotation.The consumption of macronutrients, including nitrogen with a crop of various perennial grasses, as well as the responsiveness of alfalfa, bromus and melilot to the level of nitrogen-phosphorus nutrition, were studied.The current nitrogen mobilization under these conditions of bromus vegetation on the background without fertilizers was 76 kg/ha.When optimizing the phosphate regime of the soil, this indicator increased to 99 kg/ha.Alfalfa nitrogen removal increases on similar agricultural backgrounds due to symbiotic fixed nitrogen by 89 and 193 kg/ha, respectively, or by 2,2 and 2,9 times.In such conditions, perennial legumes (alfalfa and melilot) are highly productive without nitrogen fertilizers and respond positively to improved nutritional conditions for phosphorus.This is especially evident in alfalfa of 1-5 years of life, where harvesting of green mass and fodder units increases to 40,56 and 7,00 t/ha, respectively, or by 86% and 54%, with 82,76 GJ of exchange energy per hectare.