Abstract
The requirements of precision crop management or limited water supply requires that either plant water statusbe varied during the growing season to optimize crop performance or a continuous level of limited irrigation must be practicedto match irrigation water availability. Canopy temperature (TC) has been successfully used to time irrigation applicationsfor well-watered crop growing conditions. The cumulative daily time that TC exceeds a crop-specific temperature threshold,designated as stress time (ST), is used to indicate the need for irrigation. Manipulation of the ST value required to indicatethe need for irrigation changes irrigation frequency and seasonal irrigation. The ST value that generates the irrigation signalis the time threshold (TT). This study developed a procedure for estimating the relationship between TT for cotton and seasonalirrigation rates. Data were analyzed from irrigation studies that measured the water application and cotton yield responseto a range of average daily ST. All irrigation studies included a common control TT of 330 min/d above a canopy temperaturethreshold of 28C as the criteria for the irrigation signal that maintained cotton in a well-watered status. In order to developrelationships between daily ST and final yield, or water input during the season, daily ST values were calculated and averagedover the irrigation season. The same procedure was used to calculate the average TC. The procedure for identifying controlTT to establish different crop water status levels included the following steps. First, a linear relationship was defined betweenaverage daily ST and lint yield. Second, separate linear relationships were established between average daily ST and totalwater or irrigation input. Third, based on the slope of the trend line between average daily ST and yield, 1-h differences inaverage daily ST were selected to produce sufficiently large differences in total water and irrigation input to affect yield. Theseaverage ST values were 408, 468, and 528 min/d, and corresponded with control TT values of 330, 390, and 450 min/d. Thesecontrol TT should result in different amounts of water application during the growing season and produce differences in cottonyield.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
