Mapping of reference crop water consumption and net irrigation water requirement by geographic information system

One of the most important parameters used in water resources management and development projects is plant water consumption amounts. In this research, it was aimed to determine the spatial and temporal changes of the daily average reference plant water consumption (ETo) in ten-day periods for Şanlıurfa province by using daily climate series for many years and to determine the spatial and temporal changes of the net irrigation water need (dnet) of the cotton and corn plants grown in ten-day periods. is intended to be determined. Within the scope of the purpose, provided daily for many years (2000-2021) from a total of 11 meteorological observation stations located within and outside the provincial borders of Şanlıurfa; Minimum and maximum temperature (⁰C), sunshine duration (hours), average relative humidity (%) and wind speed (m/s) data were used as basic material. With the help of the Cropwat 8.0 software program developed by FAO, ten-day average reference plant water consumption (mm) values were calculated for each station using the Penman-Monteith method for many years. Based on the ten-day average ETo values obtained, maps in which the average reference plant water consumption in ten-day periods for all months for Şanlıurfa province and the net irrigation water need of cotton and corn plants in ten-day periods for an irrigation season are determined by using the inverse distance method in the geographical information system environment. has been created. According to the study results, monthly average ETo values in ten-day periods; It varied between 7.67 mm and 89.20 mm. While there were significant increases in ETo values in the south and southeast of the province, it was determined that there was a decrease in ETo values in the north and southwestern parts under the influence of Atatürk, Birecik and Karkamış dams. However, during an irrigation season, the highest dnet value for cotton and corn plants was determined as 112.78 mm in the third ten-day period of July for the cotton plant, while it was determined as 92.90 mm in the third ten-day period of August for the corn plant. It is recommended that the ETo values obtained as a result of the study be taken into account in determining the plant water consumption (ETc) of the plant pattern of the region and the net irrigation water needs of the cotton and corn plants grown in an irrigation period. At the same time, it is thought that the study will contribute to the literature.