Improving water use in rice irrigation systems
Purpose: improving methods for operational correction of water use and water distribution management in rice irrigation systems. Materials and methods. The generally accepted methods of field experiments, water balance experiments in the field and hydrological lysimeters, analysis and synthesis were used in the research. Results. The algorithms for calculating evapotranspiration of rice and companion crops of rice crop rotation by meteorological parameters have been developed, that allow calculating the rice evapotranspiration daily based on average daily data on air temperature, relative air humidity, wind speed and precipitation, calculating evaporation from water surface, quick determining water consumption and correcting water distribution in the irrigation network, on the basis of the developed bioclimatic coefficients in relation to evaporation from the open water surface and according to the correction factors for evaporation from the water surface of rice fields, as well as companion crops of rice crop rotation. Conclusions. The data obtained from the study in the field and hydrological lysimeters allowed obtaining dependences for rice transpiration and water evaporation from the rice fields water surface, determining the proportion of water losses in rice irrigation systems by cost items, used in the algorithm development for calculating rice evapotranspiration, calculation of evaporation and losses, and on the basis of the algorithm, a program for an electronic computing machine (computer) to calculate the water consumption and water disposal rate of rice and related crops of rice crop rotation was developed. The developed and tested measures in the Proletarian irrigation system Rostov region in 2020 and 2021 could save about 15 % of irrigation water and the economic benefit was 1.89 million rubles per year.