Wheat productivity on the soil biological activity background in crop rotations and monosowning under the Southern Urals conditions

The purpose of the study is to establish the effect of soil biological activity and nitrate nitrogen content on the productivity of spring wheat in the arid conditions of the Southern Urals. The results of a long-term stationary experiment on the effect of the biological activity of the soil and the quantitative content of nitrate nitrogen in the soil on the yield of soft spring wheat in crop rotations and monosowing on two backgrounds of mineral nutrition are presented. The experiment was carried out on a stationary site in the Orenburg Region. The vegetation periods of the study are assigned to three groups of aridity, and 14 out of 20 years correspond to very dry ones with HTC equal to 0.6 units or less; 2 years (2003 and 2013) out of 20 were characterized as slightly dry. The cultivation of soft spring wheat in the system of multi-field, permanent crops is considered. The highest percentage of biological activity of the soil was established in the variant of the aftereffect of peas both on a fertilized background (31.4 %) and unfertilized (10.2 %). Cultivation of soft spring wheat in multi-field in the aftereffect of peas and millet leads to an increase in crop yield. Yields of spring wheat on average for 2002-2021 in the aftereffect of the predecessors, peas and millet amounted to 0.98 and 0.97 tons with the application of mineral fertilizers and 0.93 and 0.90 tons per 1 ha against the background without fertilizers, respectively. The use of mineral fertilizers leads to an increase in the biological activity of the soil, the content of nitrate nitrogen and, as a result, the productivity of an agricultural crop. On average, over 20 years of research, there is a close relationship between the yield of spring wheat and the biological activity of the soil in the aftereffect of millet: on a fertilized background - 71.5 %, on an unfertilized background - 68.7 %.