Irrigation Withdrawal Time, Nitrogen Fertilization, and Cultivar Maturity Interactions in Upland Cotton
Sep 12, 2018
Normal cotton management practices in South Texas terminate irrigation as early as first open boll (about 6 weeks after first bloom) and use N fertilization rates ranging from 135 to 200 kg/ha. Experiments were conducted at the Texas A&M University Agricultural Research and Extension Centre in Uvalde, TX during the 1995, 1996, and 1997 seasons. This study evaluated growth and yield responses of very early, early, medium, and medium late maturing upland cultivars to early termination of irrigation and reduced level of N fertilization. Termination of irrigation three wk after early bloom did not decrease yields. High rates of N fertilization do not increase yields. Very early and early cultivars showed superior yield performance when soil moisture availability is plentiful during early season. DP5409 showed superior yield performance in all three years, including the droughty 1996. Medium-late DP90 produced superior yield under early-season droughty conditions and heavy early boll set. Earlier than normal termination of furrow irrigation and lower than normal nitrogen fertilization rates appear to be feasible practices leading to reduced-input production. Selection of appropriate cultivars is key for superior yield performance.