field quantification of crop water stress

ABSTRACT CANOPY temperature is used to quantify crop stress by use of a crop water stress index (CWSI). The index can be developed empirically and theoretically and advantages of each approach are described. Relationships between the CWSI and traditional plant stress parameters such as leaf water potential and stomatal conductance are presented for cotton. The daily change in CWSI for cotton shows its dynamic response to changing atmospheric demand and soil moisture conditions. The value of the CWSI is shown in terms of scheduling irrigations and predicting lint cotton yield.