• Late Planted DPL451BR Cotton Responses to Plant Growth Enhancement Products Applied at Three Crop Development Stages in Palo Verde Valley, 2003

      Rethwisch, M. D.; Reay, M.; Chaffin, G.; Perez, R.; Grudovich, J.; Wellman, J.; Hawpe, E.; Tronstad, Russell; Husman, Steve; Norton, Randy (College of Agriculture, University of Arizona (Tucson, AZ), 2004-05)
      An experiment to investigate the effects of several plant growth enhancement products (AuxiGro7 WP, FirstChoice7 Bollster, CalMax, FoliGro7 BollSet) on DPL 451BR was conducted in the Palo Verde Valley. The cotton field chosen for this project was planted in April 2003, and flowering and boll/lint production was highly affected by summer heat, therefore product effectiveness was tested under the extreme high temperatures conditions that existed in 2003. Products were applied July 11 (shortly after first bloom), August 1st and/or August 15. Three rates (1, 2, 4 oz./acre) of AuxiGro7 WP were applied at each date, although just a single rate of other products was evaluated. Data collected included plant mapping following the first two application dates as well as lint yield and quality at harvest on October 20-23. Data indicated rate effects for treatments containing AuxiGro7 WP as noted in response to applications on August 1 (retention rates) and August 15 (cotton quality factors). These responses were signficantly different than the untreated check, and were often signficantly different than the Bollster fertilizer treatment itself as though Bollster was also included with AuxiGro7 WP treatments. Although yields for any treatment and the untreated check were not significantly different, previously noted differences for retention for the AuxiGro7 WP treatments may not have been realized due to the high temperatures and extended periods of not only Level 1 but Level 2 stress during the course of the experiment. Cotton values per acre were highest ($609.85/acre) in the 4 oz/acre of AuxiGro7 applied on August 15, due to highest valued lint as a result of micronaire of 5.2 combined with increased fiber strength and fiber length. Application of CalMax resulted in a significant increase in fiber strength following two applications of 4 oz./acre of AuxiGro7 + Bollster, but CalMax following two applications of Bollster did not affect fiber strength when compared with each of the two application treatments. A third application of FoliGro7 BollSet was detrimental for cotton yields and strength compared with only two applications of this product, although both treatment regimens resulted in shorter fibers that were not quite as strong as the untreated check.
    • Mepiquat Formulation Evaluation in southeastern Arizona

      Norton, E. R.; Clark, L. J.; Tronstad, Russell; Husman, Steve; Norton, Randy (College of Agriculture, University of Arizona (Tucson, AZ), 2004-05)
      A series of experiments were conducted in 2003 in the Upper Gila River Valley in Safford, AZ to evaluate several different formulations of the plant growth regulator (PGR) Pix manufactured by BASF. Two experiments were conducted at the Safford Agricultural Center (SAC) while the third was conducted on a grower-cooperator field in the same valley. Experiments conducted at SAC involved evaluating the four formulations of Pix (Pix, Pix Plus, Pix Ultra, and Pentia) in a standard (STD) treatment regime and a low rate multiple (LRM) regime. The untreated control plots in both the LRM and STD experiments produced higher yields than any of the other PGR formulations. Comparing only the PGR formulation treatments the Pentia treatment produced the highest yield in both the STD and LRM experiments. No significant differences were observed in fiber quality for either the LRM or STD experiment. The third experiment conducted on a growercooperator field was a Pentia demonstration experiment. Three treatments including a control, a standard, single Pentia application, and an aggressive split application of Pentia were employed. The highest yield was produced in the most aggressive Pentia treatment. Results from this set of experiments demonstrate the importance of incorporating information from plant monitoring techniques when making decisions about PGR applications.