Assessing of The Water Salinity Effect in Surface Irrigation on Index Rate CWSI (Crop Water Stress Index) for Scheduled Summer Maize

Irrigation scheduling with salinity and stresses, is much more difficult than Full irrigation. Using canopy temperature for plants irrigation scheduling is one of the methods that have been attention by many researchers. On of the usual method is presented by Idso. This research intends to investigate irrigation scheduling of summer maize using crop canopy temperature in Ahvaz climate (2013-2014) using surface irrigation with two levels of salinity irrigation water( S1=2.5 ds/m ,S5=5 ds/m).Crop water stress index(CWSI) is calculated for the two treatments. The experiment had three replications. With due to the obtained results, The CWSI for the two treatments S1 (minimum salinity) and S5 (maximum salinity) in September 14 and October 15 were 0.26 and 0.22. Upper baseline for the S1, in September and October are 5.05 C0 and 4.975 C0 respectively. For the S5 treatment the upper baselines in September and October were 2.85 C0 and 2.60 C0 respectively. Lower baseline also were calculated for the treatments. That was represented It is found that the S1 lower baseline is lower than the S5 treatment. This is due to the S5 treatment was effected By tension more than the S1 treatment. By using of measured data for scheduling irrigation maize in October and September with surface irrigation methods, some equations were determined. By using of the equations and comparing measured with the calculated canopy and air temperature, time of irrigation can be detected.