Influence of moisture regime of dark gray forest soil on spring wheat yield

In a stationary two-factor experiment in 2011–2020 in the conditions of the Middle Urals, the moisture regime of dark gray forest heavy loamy soil was studied depending on the type of precursor of spring wheat in crop rotations and the nutrition background. Soil moisture in the arable and subarable horizons largely depended on the conditions of the previous year and precipitation in the winter-spring period. Minimum moisture reserves in the spring in the 0–20 cm layer at a level of 21–30 mm were noted in 2011 and 2013, which was preceded by drought conditions. The combination of mineral and organic fertilizers in crop rotations provided a reliable increase in the moisture content of the arable layer by 4.0–5.8 mm compared to the control, in relation to the mineral nutrition background - by 1.8–3.1 mm. This trend persisted during the period from germination to heading. A direct relationship was established between moisture reserves in the 0–20 cm layer at the beginning of the growing season and wheat yield, the correlation coefficient was 0.626–0.840. No significant differences in moisture accumulation in the arable layer were found between the predecessors. During the interphase period from sowing to tube emergence, soil moisture in the 0–20 cm layer decreased by a total of 13–15.0 mm compared to the sowing period (29.0–36.4 mm), mainly due to water evaporation with an open soil surface. On cultivated dark gray soil under favorable weather conditions (GTC – 1.31), it is possible to obtain a grain harvest of 3.0 t/ha or more in the control variant. With uniform distribution of precipitation against the background of moderate air temperatures during the growing season in 2017, with the application of fertilizers, the maximum wheat yield was achieved in the range of 5.45–5.76 t/ha, which is close to the potential of the Krasnoufimskaya 100 variety (6.0 t).