Investigation of cotton water stress index variations under different water and fertilizer systems

This study was conducted at the experimental field of the, Department of Agricultural Structures and Irrigation, Faculty of Agruculture, University of Cukurova in 2005.This study was investigation of cotton water stress index varriations under different water and fertilizer systems. Three different irrigation treatments were applied in this study. The first irrigations were applied to increase the soil moisture to field capacity with considering leaf water potential. The following applied irrigation water amount was based on free water surface evaporation from a screened Class-A Pan. Weekly cumulative evaporation values were applied to 100% I1, 70% I2 and 50% to I3 treatments. In this research a total of 493, 316 and 163 mm of irrigation water were applied to I1, I2 and I3 respectively. Grain yield obtained from the above mentioned irrigation treatments was 312, 349 and 334 kg/da.As a result of the study CWSI values determined for I1, I2 and I3 were 0.06, 0.15 and 0.30 respectively. According to these results the highest yield get from I2 , thus, CWSI could be useful to determine irrigation time.Thus, CWSI = 0.30 could be used as a criterion.