Satellite-based monitoring of water productivity of irrigated wheat in Urmia Lake basin using RUE and SEBAL algorithms and Landsat 8 and 9 images

Considering the status of water resources in the Urmia Lake basin (ULB) and the necessity for real-time monitoring of crop production and water consumption in this area, the objective of current research was to calculate actual evapotranspiration (ET a ), actual crop coefficient (K c act ), water consumption, dry biomass, grain yield, and water productivity of irrigated wheat in the ULB using remote sensing techniques. For this purpose, the ULB was divided into six sub-basins. To calculate reference evapotranspiration (ET o ), meteorological data and the FAO56 Penman-Monteith (P-M) equation were used, and ET a was calculated utilizing the Surface Energy Balance Algorithm for Land (SEBAL) and 43 Landsat 8 and 9 satellite images. Furthermore, to calculate biomass, grain yield, and crop water productivity (WP c ), the Radiation Use Efficiency (RUE) model was employed. In this study, 1115 irrigated wheat farms were monitored. The results indicated that the average ET o in the ULB during the irrigated wheat growing season is 802 mm. Also, K c act differed from FAO coefficients (K c ) across growth stages, being higher during initial and final stages but lower during development and intermediate stages. According to the results, the average water consumption volume for the entire basin was determined to be 4566 m 3 /ha. Also, the overall average Harvest Index (HI) for the ULB was found to be 0.42. The results of the biomass and grain yield investigation revealed significant differences in their values among different sub-basins. Additionally, the overall average WP c for irrigated wheat in the ULB was calculated to be 0.94 kg/m 3 . • Satellite data enhances water management in Urmia Lake basin, aiding real-time crop monitoring. • Crop coefficients (Kc) deviate from FAO recommendations, varying across growth stages. • Water consumption in Urmia Lake basin is lower than FAO estimates. • The Radiation Use Efficiency (RUE) algorithm provides highly accurate estimates of wheat yield.