Irrigation Scheduling on Long and Short Staple Cotton, Safford Agricultural Center, 1989

Two irrigation scheduling trials were performed in 1989, one for short staple and one for long staple. Yields in the trials were very good with the best treatments yielding over 1700 and 1600 pounds of lint per acre for DP 90 and S-4 respectively. The treatment using Infrared thermometry was the best overall treatment in the short - staple trial, with the highest yield, the highest percent first pick, the shortest plants, the lowest water use and the highest water use efficiency. The two computer methods were very close to the IR treatment in yield and percent first pick, but grew taller plants with more water and were not as efficient with their water use. The trial on long staple cotton was encouraging in that reasonable yields were obtained using short-staple parameters. The computer model using AZMET data yielded significantly lower than the other treatments, indicating that we need to refine the evapotranspiration crop coefficients