SURFACE RUNOFF OF MELTWATER AND STORMWATER FROM THE TERRITORY OF ORDINARY SLOPING CHERNOZEMS OF THE NORTHERN AZOV REGION IN A CHANGING CLIMATE

Soil erosion is one of the main factors in the degradation of chernozems, causing the greatest damage to agricultural land as a result of land development. The load on the soil has increased especially in recent decades, due to the intensification of agriculture, an increase in yield and a reduction in the return of nutrients to the soil, which led to a change in the physical properties of chernozems. Therefore, the purpose of the study was to study the intensity of runoff of meltwater and stormwater in crop rotations of various designs in the territory of sloping agro-chernozems in a changing climate. Field research was conducted in the Rostov region of Aksai district in a long-term field experiment to study crop rotations and tillage techniques in 1990–2024. The experimental site is located on an erosion-hazardous slope of the southeastern exposure with a steepness of up to 3.5–4°, the organization of the slope territory is a contour-landscape system. The soil cover of the site is represented by ordinary carbonate medium-washed medium-bulk low-humus heavy loam on loess-like loam. As a result of the changing climate, a change in runoff formation processes has been noted in recent decades. Climate change is manifested in an increase in the average daily air temperature and a decrease in precipitation, both throughout the year and during various periods of melt and storm runoff formation. There has been a decrease in snow cover in recent years or its absence in the fields, while the number of extreme downpours is increasing. The values of the average daily air temperatures at which intensive runoff begins have been established. The dependence of water runoff on the intensity of heavy rains and the amount of precipitation has been revealed. An increase in the share of perennial grasses in the crop structure of soil-protective crop rotations to 40% reduced runoff by 39.3–58.1%, and the use of soil-protective tillage by 21.0–23.7%. The use of anti-erosion measures such as the organization of the slope area, the use of soil-protective crop rotations and tillage methods, etc., can reduce runoff to safe limits, and in some cases completely prevent it.