Variation of cotton leaf water potentials under different irrigation and fertigation systems

This study was carried out at the experimental field of the Department of Agricultural Structures and Irrigation, Faculty of Agriculture, University of Çukurova in 2005.In this study, variation of leaf water potential (LWP) has been checked in water potential versus to time of cotton plant at different irrigation schedules. In this study, 3 different systems have been formed due to irrigation schedule which includes various Nitrogen amounts. Other irrigations were performed due to every one week conglomerated evaporation results that obtained from open water surface evaporation pot (class A pan). %100 of cumulative evaporation results was applied to I1 treatment, %70 of cumulative evaporation results was applied to I2 treatment, %50 of cumulative evaporation results was applied to I3 treatment. 40 ppm Nitrogen has been applied with irrigation water.Due to result of study, 493, 316 and 163 mm irrigation water have been applied to I1, I2 and I3 experimental treatments in order. In these irrigation topics, mass efficiencies are 312, 349 and 334 kg/da. Obtained reaping index values are 0.20, 0.29 ve 0.38 in order. YSP results were given as follows below as to treatments YSP =-15.5 bar , Complete Irrigation was performed at (I1) treatment.YSP =-17.8 bar , Low stress was performed at (I2) treatment. YSP = -20.1 bar , Low stress was performed at (I3) treatment. The highest yield has been obtained at I2 treatment according to these results. That results can be useful to designate the irrigation time and it is fixed that YSP = -17.8 bar value can be taken as a criterion to designate the irrigation time.