The Use of Primed Acclimation and Strip Tillage to Increase Water Use Efficiency in Cotton

Upland cotton (Gossypium hirsutum L.) is a crop well suited for the southeastern United States, with over 3 million acres harvested in 2007 (USDA Ag. census, 2007). Unreliable rainfall in the Southeast has caused many growers to install irrigation systems. It is imperative for growers to use this resource efficiently to increase profitability and conserve limited resources. Reduced tillage has been shown to increase soil water infiltration, increase soil water content, reduce bulk density and soil compaction. Additionally, reduced tillage has been shown to increase yields in cotton. Adjusting irrigation scheduling may be another way to decrease water inputs and increase water use efficiency. Unpublished data on peanut and cotton from Texas and Georgia suggest that it is possible to place a mild water stress on a crop (less than full evapotranspiration replacement) during the early part of the growing season without having negative effects on yield. This strategy has been termed primed acclimation (PA) and seems to change the physiology of the crop to have a deeper and more prolific rooting system by decreasing the carbon allocation ratio of shoots to roots, while saving water. To further validate the efficacy of these management strategies for water conservation, a large research project is being conducted at the University of Florida, Plant Science Research and Education Unit. The treatments being tested consist of conventional and strip tillage (reduced tillage), as well as irrigation treatments that apply 100%, 60%, 60PA (60% during vegetative growth and 100% during reproductive growth), and 0% of evapotranspiration. To characterize the environmental and physiological responses to these treatments, we will be measuring soil moisture and temperature, canopy temperature, root architecture, canopy development, and cotton yield and grade. We hypothesize that the combination of reduced tillage and PA will allow for the greatest water savings and highest yields.