• Initial Post Plant Irrigation Effects on Low Desert Upland Cotton Yields Using Leaf Water Potential Measurements

      Husman, S. H.; Barrot, D. J. Jr.; O'Leary, J. W.; Moore, M.; Wegener, R.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 1994-03)
      Leaf water potential (LWP) measurements using a pressure chamber were used to determine optimum timing of the first irrigation following planting on Upland cotton in 1992 and 1993. Previous studies have indicated that leaf water potentials are dependent on the vapor pressure deficit (VPD) of the surrounding air. As a result, the VPD was accounted for in the development of a Leaf Water Potential Index (LWPI). The field studies consisted of three irrigation treatments with four replicates arranged in a randomized complete block design (RCB). Targeted treatment thresholds were 0.15 LWPI (wet), 0.30 LWPI (medium), and 0.45 LWPI (dry). Timing of the first irrigation for the 1992 study occurred at 36, 53, and 63 days after planting. Timing of the 1993 first irrigation occurred at 50, 61, and 77 days after planting for the wet, medium, and dry treatments respectively. There were no significant lint yield differences between irrigation treatments in both 1992 and 1993.
    • Upland Cotton Variety Resposne to Row Spacing

      Husman, S. H.; Silvertooth, J. C.; Jech, L. E.; Wegener, R.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 1994-03)
      An Upland cotton row spacing study evaluation 30 in. vs. 38 in. rows was conducted in the Gila Valley of western Maricopa County in 1993. In addition, six Upland varieties were also evaluated on both the 30 and 38 in. row configurations. There were no row spacing differences in yield among five of the six varieties. Sure Grow 1001 had significantly lower lint yields when produced on 30 In. rows. DPL 5415 had significantly higher lint yields that the other five tested varieties on 38 in. rows. There were no variety differences in the 30 in. rows.