Zhuravlov O. Scientific and practical substantiation of methods of soil water regime management in irrigated conditions

In the thesis it is given theoretical generalization and results of experimental researches which solve an important scientific and applied problem of substantiation of methods for determining evapotranspiration and irrigation of crops in the management of soil water regime. According to the research results, the methods of soil water regime management by instrumental, calculation and phytomonitoring methods have been improved. Functional relationships between soil moisture and sensor performance have been established: Sentek Drill & Drop; Decagon Devices – 10HS, EC5, Aqua Spy CTG-02; WaterScout SM-100, Watermark 200SS, which are used in Internet stations of soil moisture and hand-held devices AQUATERR M-350, НН2 (sensor SM-200), МГ 44. Scientific and methodological approaches to irrigation planning by phytomonitoring methods are substantiated. Adapted calculation methods: Penman-Monteith, A.M. and S.M. Alpatyev, D.A. Shtoyko, M.M. Ivanov for the conditions of the Steppe of Ukraine in modern conditions of climate change, for a number of vegetable, grain, oilseeds and row crops, the coefficients used to calculate the actual evapotranspiration by these methods are specified. The influence of water stress on evapotranspiration of agricultural crops is investigated and a mathematical model of water stress coefficient Ks is developed. Regularities of water exchange, water consumption and formation of productivity of agricultural crops in the conditions of irrigation are established. It was found that there is a close linear relationship between the intensity of transpiration of tomato plants by solar radiation, relative humidity and air temperature, as indicated by pairwise correlation coefficients, which are 0,99, 0,96 and 0,94 respectively. According to the results of correlation-regression analysis of the data, a model of the dependence of the intensity of transpiration of tomato plants during the day on environmental factors was obtained. Calculations of economic and energy efficiency of soil water regime management methods are performed. Key words: instrumental method, calculation method, phytomonitoring methods, soil moisture sensors, water stress coefficient, evapotranspiration, culture coefficient, soil water regime.