Features of water regime changes of steppe chernozem in the South-East of Central Chernozem zone in modern conditions

Abstract

The article presents an analysis of the elements of the water regime of the steppe chernozems of the Stone Steppe of the Central Chernozem Region in the conditions of the dry period from the end of 2019 to the autumn of 2020. The objects of the study were: the mowed fallow land plowing in 1882, the old-growth forest strip of 1903 planting and arable land adjacent to fallow plots. The soil-hydrological constants were calculated (total water capacity, lowest field capacity, permanent wilting point) both in the time interval and down the soil profile to a depth of 2 m. The reserves of productive moisture during the growing season were also studied. The maximum values of productive moisture content was reached on the mowed fallow sites by the beginning of February, the minimum in the forest belt areas, the arable land plots had an intermediate value. By the middle of the growing season (June), 2020, the moisture reserves in the soils of the forest strip, fallow and arable land were 127, 123 and 109 mm, respectively, in the meter thickness. The highest amount of productive moisture in the upper soil horizon (0-20 cm) is observed under the forest belt – 39 mm. However, moisture content under the fallow land in the upper horizon had decreased to rate of the dead moisture reserve by early August. Similar values were found in soil under the forest belt and arable land. Otherwise, moisture profile was formed in underlying carbonate horizons. The forest belt soils in insufficient atmospheric moisture conditions in 2020 were more dried out than soil of fallow and arable land. The estimation was given for nature of soil profile changes of soil moisture profile due to influence of forest belt. The data of productive moisture reserves in soil at different distances from the forest belt were presented. In the meter layer at the edge of the forest belt, moisture reserves were at the level of 94.0 mm, sharply decreasing to 60.3 mm at a distance of 25 m from the forest strip, with a gradual decrease to 34 mm at a distance of 125 m. The results of observations showed a clear downward trend of productive moisture content due to distance from the old-growth forest belt.