• Upland Advance Strains Cotton Variety Test at the Maricopa Agricultural Center, 1995

      Hart, G. L.; Nelson, J. M.; Clark, L. J.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 1996-03)
      Eighteen upland cotton advance strains were grown in a replicated trial at the Maricopa Agricultural Center. Lint yield, boll size, lint percent, plant population, plant height and fiber property are presented in this report.
    • Upland Cotton Water Stress Sensitivity By Maturity Class

      Husman, S.; Metzler, F.; Wegener, R.; Johnson, K.; Schnakenberg, L.; Brown, P.; Martin, E.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 1996-03)
      Lint yield response to three irrigation treatments based on allowable soil moisture depletion regimes of 50, 75, and 100% depletion of available soil moisture was tested on both a determinate (D&PL 5415) and an indeterminate (D&PL 5816) upland cotton. Arizona Meteorological Weather Networks' (AZMET) potential evapotranspiration (ETo) estimates in combination with cotton crop coefficients were used in a summation manner until targeted depletion thresholds were reached which then triggered the desired irrigation event. The experiment consisted of three irrigation treatments with each main irrigation treatment containing both the determinate and indeterminate variety selection resulting in a randomized complete block split plot design. Actual irrigation volume delivered was 46, 42, and 32 acre inches /acre in 1994 and 52, 48, and 36 acre inches /acre in 1995 for the wet, medium, and dry treatment respectively. Lint yields were significantly reduced in 1994 when available soil moisture depletion exceeded 75% in the determinate variety with no significant yield differences in the indeterminate variety in 1994 across all irrigation treatment regimes. In 1995, lint yields were down across all treatments and varieties with the only statistically significant reduction in lint yield (relative to all 1995 yields) occurring in the dry indeterminate block
    • Upland Regional Cotton Variety Test at the Maricopa Agricultural Center, 1995

      Hart, G.; Nelson, J. M.; Clark, L. J.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 1996-03)
      Twenty-seven upland cotton varieties were grown in a replicated test at the Maricopa Agricultural Center as part of the National Cotton Variety Testing Program. Lint yield, boll size, lint percent, plant population, plant height and fiber property data are presented in this report.
    • Weed Control in Roundup Ready® Cotton: Preliminary Experiments

      McCloskey, William B.; Dixon, Gary L.; Moffett, Jody E.; Silvertooth, Jeff; Department of Plant Sciences, University of Arizona, Tucson, Arizona (College of Agriculture, University of Arizona (Tucson, AZ), 1996-03)
      The efficacy of Roundupm herbicide for the control of common Arizona weeds in Roundup Ready® cotton was evaluated in field studies conducted at the Maricopa Agricultural Center in 1995. Promising results were obtained with 1 lb a.i./A (1 quart/A) over-the-top band applications of Roundup when cotton had 1 to 2 true leaves followed by a second, "sloppy", post-directed application ofRoundup at 1 lb a.i./A when cotton had 4 to 5 true leaves. Excellent control of small Palmer Amaranth, Wright Groundcherry, and annual morningglory seedlings was obtained with each 1 lb a.i./A Roundup application in the broadleaf weed study. The two sequential 1 lb a.i./A Roundup applications kept plots free of broadleaf weeds until layby. In the nutsedge weed control study, it was found that nutsedge plants treated with a single 1 lb a. i./A application of Roundup were stunted and exhibited leaf chlorosis, but efficacy was marginal with weed control ratings of only 40 to 50 percent. Nutsedge control ratings for an application of norflurazon (i.e., Zorial) alone or combined with Roundup applied at the 1 to 2 true leaf stage of cotton were 63 and 75 percent, respectively. Two sequential applications of Roundup at 1 lb a.i./A, both with or without norflurazon, resulted in about 90 percent nutsedge control. Roundup Ready cotton exhibited good tolerance to two sequential early season 1 lb a.i./A Roundup applications, as made in these studies, with no apparent seed cotton or lint yield reductions.