Response of Cotton Varieties to Irrigation Evapotranspiration Replacement.

With increasing concerns about declining levels of the aquifer in the Mississippi Delta, there is much interest in improving water management techniques to improve overall water use efficiency. An experiment was conducted in Stoneville, MS to provide insight into the actual crop demand for supplemental irrigation in cotton. Irrigations in cotton were scheduled using FAO-56, a standard that takes into consideration crop water demands based on growth stage and climatic data to alleviate drought stress.  The experiment was conducted as a split-split-plot arrangement in a randomized complete block design.  The main-plot factor was irrigation based on five evapotranspiration levels. The sub-plot factor was variety and included five commercial varieties commonly planted in Mississippi.  The sub-sub-plot factor was PGR use and included an untreated control or a split application of PGR at pin-head square and first bloom.  Results have not been fully analyzed at this time.