A Method for Establishing Crop Coefficients for Drip and Sprinkler Irrigated Cotton

Accurate irrigation management continues to be a primary consideration in maximizing yields and returns for cotton in arid and semi-arid regions worldwide.  But farm water delivery system limitations are often a determining irrigation scheduling constraint, particularly during periods of peak evapotranspiration that have the greatest potential for limiting crop yield and potentially reducing cotton fiber quality. Working with a Fresno County grower, large-scale experimental trials were conducted in 2010 and 2011 to evaluate a new method for irrigation scheduling that uses pre-plant field data to establish a crop coefficient early in the season in an effort to improve whole farm irrigation management planning.  The results presented highlight the value of stored soil water and illustrate how in-season irrigation deficits are linked to water stress that can be managed to minimize deleterious crop water stress levels.