This article discusses the mathematical model of furrow irrigation to establish irrigation rates when watering cotton through a screen from an interpolyme complex (IPC) with the addition of mineral fertilizers. By the change in “I” when watering cotton through a surface screen from IPC with the addition of mineral equations, we can say that physically the effect of the screen will affect the amount and rate of infiltration «I» and “ϑI ”, other relations do not change. In the case of placing the screen in the form of a thin film (as experiments show), soil infiltration decreases by approximately 3-3.5 times.

In the world, special attention is paid to targeted research on water resources management and efficient use of irrigation water resources. In this regard, one of the main tasks is to improve the technique of irrigation of fields using cheap chemical and technical means, the development of new methods of water-saving irrigation, the development of the theory of water-saving technologies in irrigation of fields. In this regard, the use of inexpensive interpolymers to reduce soil composition and irrigation water infiltration is of particular importance.

The problem of global climate change is on the agenda of mankind, not only because of the average annual temperature rise on the planet but also because of changes in the entire geosystem, rising global oceans, melting ice and permanent glaciers, increasing uneven rainfall, changing river flow patterns and climate instability, other changes involved. The world pays special attention to research work to develop technologies for the management and efficient use of water resources. In particular, it is important to conduct research to develop new water-saving irrigation technologies using cheap and chemical, and technical means.

The purpose of this article is to analyze the monitoring data of irrigated land in the agrometeorological conditions of Kashkadarya region and CropWat 8.0. is to estimate and compare actual daily evapotranspiration (ETo) and seasonal irrigation rates of cotton and spring wheat using the model. These studies were conducted in experimental fields located in the main agricultural production zone of Kashkadarya. At the time of global climate change, and in order to prevent the decrease in the yield and quality of agricultural crops due to the lack of irrigation water compared to the crop demand, taking into account the water demand of cotton and winter wheat grown in Kashkadarya region, using the weather station data, the seasonal irrigation standard FAO methodology using the CropWat 8.0 program, the mechanical composition of the soil, the depth and mineralization of seepage water, and the values of the plant coefficient for the stages of cotton development were determined. In addition, scientifically based irrigation methods of water-saving irrigation technology of cotton and winter wheat were developed for the conditions of the Kashkadarya region according to the generally accepted hydromodule regions. Based on the developed software, the seasonal irrigation norms of cotton and winter wheat were 3500–6900 (cotton) and 2000–3400 (winter wheat) m3/ha in hydromodule regions. These values were compared with the results obtained from field experiments. The results of the study showed that the ETo values calculated by the method based on the CropWat model compared with the values obtained from field experiments, the difference was ± 8–10%.