Dynamics of water balance elements and periodic flushing regime of leached chernozem

The lysimetric method of studying the characteristics of the water balance is the most accurate means of assessing the water regime of the soil. Observations carried out at the lysimetric station for 35 years showed that the discharge of gravitational moisture from a meter-thick layer of leached chernozem occurred annually in the spring after the melting and thawing of snow. A discrete nature was observed during the infiltration of summer and autumn precipitation. During the summer period, the outflow of rainwater was noted on average once every 3.5 years. The discharge of the autumn pool of precipitation into groundwater occurred approximately once every two years. The most intense was the winter-spring outflow of moisture into groundwater. Over 35 years, on average 204 mm of precipitation fell from November to April, and the discharge of gravitational water during this cycle averaged 117 mm, or 57% of the amount of winter-spring precipitation. The average gravitational runoff over 35 years was 50 mm, or 36% of the total. In autumn, either with downward outflow, excess moisture was discharged, or this volume was added to the winter-spring precipitation pool. During the summer period, an average of 150 mm fell as rain per year. Annual losses of summer precipitation with gravitational runoff are small - an average of 13 mm. The largest water discharge (136 mm) during this period was noted in the 1989-1990 hydrological year. In other years, it, as a rule, did not exceed 50 mm. In the zone of unstable moisture over the years, with a periodically flushing type of water regime formed, on soils of heavy granulometric composition, it is necessary to use moisture-accumulating methods of soil cultivation in the technology of cultivating field crops, which help reduce the stress of the water balance in the active root-inhabited soil horizon.