Increasing the efficiency of rice irrigation systems under conditions of man-made threats and increasing water scarcity in the South of Russia

Rice irrigation systems are complex management objects, as they have a large number of difficult-to-control criteria and indicators, such as the level and mineralization of groundwater, secondary salinization, melioration and granulometric composition of the soil, etc. Management of such indicators and criteria is complicated by the periodic presence of a water layer on the rice paddy, the duration of which depends on the type of flooding of the rice paddy. In turn, the type of flooding also depends on many factors and criteria, such as soil and climatic conditions of the region, water availability, degree of soil salinity, cultivation technology and varietal characteristics of rice. However, all these criteria and indicators can be controlled to one degree or another by the collector and drainage network of the rice irrigation system. Therefore, with the correct, rational use of drainage, it is possible to significantly reduce the costs of material and labor resources in rice cultivation and reduce the risks of crop decline or loss. Therefore, the goal of our research is to develop recommendations for rice-growing farms in the South of Russia on the use of a collector and drainage network to maintain the ameliorative state of soils and obtain sustainable rice yields by studying the relationship between rice yield and salinization of the arable horizon and analyzing various operating modes of the drainage and discharge network. The studies were carried out in the peasant farm «Golovin Grigory Nikolaevich» of the Kalininsky district of the Krasnodar region in 2021-2024. The article provides practical recommendations for optimizing the main soil-ameliorative factors by managing vertical filtration, soil salt regime and groundwater level. The authors analyzed the dependence of the filtration coefficient of the upper meter of soil on the content of physical clay and found that the optimal value is Kf from 0.217 to 0.331 m/day, which occurs on heavy loamy soil varieties. It was found that within a few days after flooding the system, the vertical filtration rate decreases as a result of processes occurring in the soil; the optimal average vertical filtration rate (Vxopt) for vegetation on heavy loamy soil varieties is from 0.017 to 0.037 m/day. The studies carried out make an important contribution to the formation of new elements in the methodology of rice cultivation in the new conditions of increasing water shortage and man-made threats that have developed in the South of Russia.