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%.