Irrigation Efficiencies and Lint Yields of Two Upland Cotton Varieties Grown at the Maricopa Agricultural Center, 1996

A field trial was conducted at the Maricopa Agricultural Center to observe the effects of four irrigation efficiencies (65%, 75%, 85 %, and 95 %) on the lint yield produced from two upland cotton varieties (DP 5409 and SG 125). Nitrogen requirements for the crop were determined using pre-season soil samples and in-season petiole samples in conjunction with crop monitoring data collected at weekly intervals. AZSCHED was used as a guide to the irrigation timing and amount of water applied during the season. The actual irrigation efficiencies obtained were less than what was targeted. The end season results were 60, 66, 72, and 74 %, respectively. The low efficiencies are due in part to the inherent inefficiency of irrigations in the early season. There was no lint yield response to the different irrigation efficiencies, and no difference in yield between the two varieties. Lint Yields ranged from 1146 # lint/acre (SG125 at 75 %) to 925 # lint /acre (SG 125 at the 95 % irrigation efficiency)