Sugarcane Irrigation Scheduling by Combining Remote Sensing Data and SWAP Model in Mirza-Kuchak-Khan Sugarcane Agro-Industry, Ahwaz, Iran

Irrigation scheduling means applying the right amount of water at the right time. In this research, the current irrigation scheduling implemented in the Mirza-kuchak-khan Sugarcane Agro-Industry farms located in Ahwaz was compared with the actual sugarcane crop water requirement using SWAP model. Due to lack of field measured data, the SWAP model was calibrated and evaluated using LANDSAT 7 ETM+ images taken over the study area at twelve different dates during the sugarcane growing season. According to the results simulated by the SWAP model, the seasonal irrigation depth applied (2640 mm) was much more than that required by the crop and, as a result, a significant amount of irrigation water was wasted in the form of deep percolation. The water productivity was estimated to be 0.35 ton/ha.cm. In order to decrease deep percolation and improve water productivity, six irrigation plans including the possibility to reduce irrigation depth or eliminate some irrigation events, or change irrigation times were evaluated by the SWAP model. For every plan studied, an improved irrigation scheduling was suggested. According to the SWAP simulations, implementations of the suggested irrigation scheduling by eliminating some irrigation events or changing irrigation times can reduce seasonal irrigation depth by 27% and improve the water productivity by 30%. Reducing irrigation depth by 20% can also increase the water productivity by 26%. In case both scenarios mentioned can be applied together, the irrigation depth would decrease 42% and water productivity would increase 68%.