Simulation of sugarcane yield under salinity and water stress conditions with the OPDM model

Limitation of water resources and decline in the quality of soil and water have led to the use of saline water and application of management systems for reducing irrigation water. The subject of this study was to determine the effect of salinity and water stress on sugarcane yield in Iran with an operational and planning distribution model (OPDM) for 7 years (2002-2008). Irrigation scenarios consisted of the full irrigation (I-1), 85% (I-2) and 70% (I-3) of the sugarcane water requirement, and salinity scenarios were the average salinity of the Karun River, S-1 (dS m(-1)), S-2 = S-1 +2 and S-3 = S-1 +4. The root mean square error and mean bias error (0.04 and 0.02, respectively) show the low error percentages and the values of EF = 0.65 and d = 0.71 indicated the high accuracy of the yield simulation with OPDM. Significant differences were observed among the different irrigation levels and this difference in I-3 was more than in I-2. The effect of different salinity levels on yield reduction was not significant. Overall, results showed that there was an individual and combined effect of salinity and water deficit on sugarcane yield; however, the effect of different irrigation levels on the yield was more than the salinity.