• Basic Cotton Crop Development Patterns

      Silvertooth, J. C.; Brown, P. W.; Malcuit, J. E.; Silvertooth, Jeff; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1991)
      Summaries of cotton crop phenology, as a function of heat units (HU, 86/55°F limits) have been developed across a wide range of production conditions in Arizona. Optimum ranges in HU accumulations since January 1 are used to describe planting dates to maintain optimum yield potentials with full season varieties. Basic events such as the occurrence of pinhead squares, squares that are susceptible to pink bollworm, and first bloom are described in terms of HU accumulations since planting. Also, the expected ranges of HU's accumulated since planting that are required to accomplish crop cut -out are shown for three general maturity types of Upland cotton.
    • Cotton Response to Mutiple Applications of PIX, 1990

      Silvertooth, J. C.; Malcuit, J. E.; Husman, S. H.; Winans, W. S.; Hood, L.; Silvertooth, Jeff; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1991)
      Three field experiments were conducted in 1990 in Arizona to evaluate cotton crop response to several treatment regimes of multiple applications of PIX (an anti-gibberellic acid plant growth regulator). Treatment regimes used in 1990 employed higher rates of PIX/acre/application and extended times of applications later into the fruiting cycle than earlier experiments in 1988 and 1989. Similar to earlier experiments, results in 1990 demonstrated the ability of some PIX treatments to significantly reduce plant height, relative to the untreated check treatments. The 1990 cotton production season in Arizona consisted of conditions which led to excessive rates of fruit loss and abortion, and somewhat vegetative plants. Final fruit retention levels of 30 to 50% were realized in the three 1990 experiments after a period of fruit loss through July and August. Lint yield results revealed significant differences (P ≤ 0.05) between several selected treatments at only one of the locations in 1990.
    • Cottonseed Treatment Evaluations in Arizona, 1990

      Silvertooth, J. C.; Malcuit, J. E.; Silvertooth, Jeff; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1991)
      Field experiments were conducted at four locations in Arizona (Yuma, Maricopa, Marana, Safford) to evaluate 16 cottonseed treatments on cotton that included 12 on Upland (Q. hirsutum L.) and 4 on Pima (Gossvpium barbadense L.). Stand counts were taken to evaluate the effectiveness of each treatment. Statistical analysis showed no significant differences among the treatments used for the Upland cottonseed. Significant differences were found among the treatments used for the Pima cotton seed at the Marana and Safford locations only.
    • Defoliation of Pima Cotton, 1990

      Silvertooth, J. C.; Husman, S. H.; Thacker, G. W.; Howell, D. R.; Winans, S. S.; Silvertooth, Jeff; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1991)
      Five field experiments were carried out in several representative cotton producing areas of Arizona to evaluate the effectiveness of a number of defoliation treatments on Pima cotton. Variable conditions were encountered among the experimental locations in 1990 for treatment comparisons. However, it appears that consistencies in the effectiveness of several treatments for Pima defoliation offer a basis for recommendations across the state.
    • Defoliation Research on Pima Cotton at the Marana Agricultural Center in 1990

      Nelson, J. M.; Silvertooth, J. C.; Silvertooth, Jeff; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1991)
      A field study was conducted at the Marana Agicultural Center to evaluate the effectiveness of selected defoliation treatments on Pima cotton under cool weather conditions. Defoliants were slow acting at this location, probably due to cool night temperatures and dry field conditions. The combination Dropp + Def 6 + Accelerate gave good defoliation results 18 days after application. The experimental defoliant SN 597 NA 243 shows promise as a defoliant for Pima when temperatures are cool.
    • Evaluation of Date of Planting and Irrigation Termination on the Yield of Upland and Pima Cotton

      Silvertooth, J. C.; Watson, T. F.; Terry, L. I.; Malcuit, J. E.; Silvertooth, Jeff; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1991)
      Four flea experiments were conducted in 1990 in Arizona to evaluate the response of Upland and Pima cotton to dates of planting and dates of irrigation termination. Planting dates ranged from as early as 27 February in the Yuma Valley (150 ft. elevation) to 8 May at Marana (2,000 ft. elevation). Dates of irrigation termination ranged from 18 July in the Yuma Valley to 8 September at Maricopa and Marana.
    • Nitrogen Management Experiments for Upland and Pima Cotton, 1990

      Silvertooth, J. C.; Clark, L. J.; Malcuit, J. E.; Carpenter, E. W.; Doerge, T. A.; Watson, J. E.; Silvertooth, Jeff; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1991)
      Two field experiments were conducted in Arizona in 1990 at two locations ( Maricopa and Safford). The purposes of the experiments were to validate and refine nitrogen (N) fertilization recommendations for both Upland and Pima cotton. The experiments each utilized N management tools such as pre - season soil tests for NO₃⁻-N, in-season plant tissue testing (petioles) for N fertilirystatus, and crop monitoring to ascertain crop fruiting patterns and crop N needs. Results at both locations revealed a strong relationship between the crop fruit retention levels and N needs for the crop. This pattern was further reflected in final yield analysis in response to the N fertilization regimes used. At Maricopa, fruit retention levels were low, petiole NO₃⁻-N concentrations relatively high, and yield responses to higher and later applications of fertilizerN were negative. At Safford, fruit retention levels were higher, petiole concentrations of NO₃⁻-N reflected strong crop demand, and a positive response to rates of fertilizer N up to 170 lbs. N/acre was measured.
    • Short Staple Variety Demonstration, Maricopa Agricultural Center, 1990

      Malcuit, J. E.; Silvertooth, J. C.; Silvertooth, Jeff; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1991)
      A short staple variety trial was conducted on the demonstration farm, at the Maricopa Agricultural Center in 1989. Nineteen varieties, received from various seed companies, were entered into the test. Yields ranged from 829 to 1428 lbs. lint acre⁻¹ for STY 110 and STV 1324 respectively. Results from the statistical analysis showed significant differences among varieties. Those varieties that were medium to short - season maturity types yielded higher than long, full season maturity types. This difference in yield was most probably due to the hot and humid weather conditions experienced in the 1990 growing season and the varietal differences associated with heat tolerance.
    • Short Staple Variety Demonstration, Pinal County, 1990

      Malcuit, J. E.; Stedman, S.; Silvertooth, J. C.; Silvertooth, Jeff; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1991)
      Short staple variety trials were conducted for three years at Prechel Farms near Coolidge At. Six varieties were included in 1988, twelve in 1989, and eight in 1990. Results from the statistical analysis showed significant differences among varieties in each of the three tests. Lint yields ranged from 908 to 1313 lbs. lint acre⁻¹ in 1988, 2844 to 4827 lbs. seedcotton acre⁻¹ in 1989, and 695 to 1059 lbs. lint acre⁻¹ in 1990. Those varieties that were medium to short-season maturity types yielded higher than long season maturity types in the 1988 and 1990 seasons. The reverse was true in the 1989 season.
    • Upland and Pima Cotton Response to Banded Fertilizer Applications, 1990

      Silvertooth, J. C.; Thacker, G. W.; Malcuit, J. E.; Doerge, T. A.; Husman, S. H.; Silvertooth, Jeff; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1991)
      Two field experiments were established in Arizona in 1990 to evaluate the effects of banded phosphorus (P) fertilizer on cotton. Experiments involved both Upland (Gossvpium ltirsutum, L.) and American Pima (Q. barbadense L.). Banded applications of P fertilizerwere made with placement of the concentrated band of fertilizer 6 in. below and 3-6 in. to the side of the zone of seed placement. The P₂O₅ was supplied from 10-34-0. Rates of applied P ranged from 0 to 160 lb P₂O₅ /acre. In one experiment, treatments consisting of 5 to 10 lbs. Zn/acre were included in all possible combinations with the P₂O₅ treatments. In all cases, treatments in the field were arranged in a randomized complete block design with four replications. Plant measurements for plant height, flower numbers per unit area, number of mainstem nodes, and nodes to the first fruiting branch were initiated by the fifth true leaf stage to evaluate plant response in terms of growth and development. Plant tissue samples were also taken at several stages of growth from each experiment throughout the growing season. Tissue samples consisted of petioles from the uppermost fully - developed leaves. Petioles were analyzed for extractable PO₄-P. Lint yield measurements also were taken. No statistically significant differences (P ≤ 0.05) were found among any treatments for any of the plant growth parameters. The same was true with regard to petiole PO₄-P levels measured. No significant differences were detected among Upland or Pima cotton lint yields in response to the applications of P fertilizers.