IMPROVEMENT OF DRAINAGE AND DISCHARGE RUNOFF SAVING MODE ON RICE SYSTEMS IN LOW-WATER YEARS

The article addresses the issues of improving the regime of saving drainage and discharge water on rice systems in low-water years. The best conditions for rice development are created when there is a layer of water on the soil surface. Due to the presence of a layer of water and its regulation on the lands of rice systems, an optimal reclamation state is maintained. Volumes of supplied and withdrawn water from rice systems depend on relief, hydrogeological and hydrological conditions. The greatest impact on the volume of water supply and runoff is the spring flood, which falls on May - June months, which causes flooding of rice fields. The volume of drainage and discharge of rice irrigation systems of the North Caucasus is 20-75% of water supply. For rice systems located in the dryless and weakly drained zones of the Volga Delta, this volume is significantly larger and reaches 120% of the water supply. Significant filtration from the channels has a great influence on the regime of groundwater, leads to an increase in the level of groundwater in the channel zone, causing flooding, waterlogging and salinization of the territories adjacent to the channels, up to their withdrawal from agricultural use. Filtration losses from the inter-farm and intra-farm network depend on the nature of its clothes, the periodicity of work, the type of soils in which this network is laid, and the degree of turbidity of irrigation water. Depending on the different combination of these factors, the efficiency varies widely: from 0.40 to 0.97, determining a large range of losses for filtration and, accordingly, groundwater supply. In the course of the conducted studies, the regimes for improving the mode of saving drainage and discharge water on rice systems were justified precisely in low-water years. The use of various types of watering on checks and sprinkling with moisture-charging watering contributes to the removal of salts from the upper layers of the soil profile when mineralizing groundwater up to 5 g/l, and watering is desalinating.