Determination of water stress index of sugarcane in two methods of surface irrigation and sub-surface drip irrigation

By using the temperature of the canopy cover of the plant, a practical parameter called the crop water stress index (CWSI), it was determined that this index is one of the methods of checking the water requirement of the plant and it can be considered as a suitable tool for irrigation management in the field. Therefore, this research was carried out with the aim of determining the water stress index of sugarcane in two methods of surface irrigation (CI) and subsurface drip irrigation (SDI) at research station number one of Khuzestan Research and Training Institute for Development of Sugarcane and Related Industries, in June 2022. The fields included the third field culture (Ratoon 3), of the CP69-1062 variety, and were selected with four repetitions in both methods. First, the equation of upper and lower base lines for the surface irrigation method was determined as (Tc-Ta)ul=1.7 and (Tc-Ta)=-0.09VPD+1.27, respectively. Then, using the equations of the lines based on the surface irrigation method, the average of crop water stress index for subsurface drip irrigation method and surface irrigation was calculated as 0.28 and 0.66, respectively, and the equation was presented according to the irrigation scheduling of the Sugarcane in June.