• The Effects of Soil Compaction from Different Sewage Sludge Application Methods on Cotton Growth and Yield

      Ottman, M. J.; Day, A. D.; Coates, W. E.; Solomon, M.; Pepper, I. L.; Taylor, B. B.; Silvertooth, Jeff; Isbell, Joan (College of Agriculture, University of Arizona (Tucson, AZ), 1989-03)
    • Energy Consumption and Yields for Cotton Tillage Systems

      Rein, B. K.; Thacker, G. W.; Coates, W. E.; Silvertooth, Jeff; Isbell, Joan (College of Agriculture, University of Arizona (Tucson, AZ), 1989-03)
      The energy consumption of 2 alternative tillage systems for continuous cotton production in Arizona were compared to a conventional system. The tests were conducted at the University of Arizona Marana Agricultural Center. Results of the study in a Pima I clay loam soil showed the sundance treatment to have the lowest energy requirement of 39 Hp-hr /ac (73 kW-h/ha); the USM system had the second highest of 58 Hp-hr /ac (107 kW-h/ha). The conventional system required 67 Hp-hr /ac (124 kW- h/ha). Average yields for all 3 systems were not significantly different. A continuation of this study will be conducted to determine long-term effects on energy consumption, yields, and soil compaction.
    • Evaluation of PIX Multiple Application Treatments on Upland and Pima Cotton in Arizona, 1988

      Silvertooth, J. C.; Howell, D. R.; Farr, C. R.; Malcuit, J. E.; Silvertooth, Jeff; Isbell, Joan (College of Agriculture, University of Arizona (Tucson, AZ), 1989-03)
      Four field experiments were conducted in Arizona in 1988 to evaluate the effects of various multiple application treatment combinations of PIX on the growth and development, as well as the lint yields of both upland and pima cotton. Plant height was significantly reduced (P ≤ 0.05) in some FIX treatments in comparison to the checks for short periods of time after the treatment applications. Those effects did not persist, nor did they translate into any significant positive differences among treatments in terms of lint yields for either of the upland or pima experiments.
    • Final Irrigation Timing of Upland and Pima Cotton

      Farr, C.; Silvertooth, Jeff; Isbell, Joan (College of Agriculture, University of Arizona (Tucson, AZ), 1989-03)
      Irrigation termination trials were continued in 1988 to evaluate a newer, popular upland variety and pima S-6. Irrigation in the first week of September increased the yield of a May planting of DP 77, but not of two trials in 1988 with early April planting dates. A March planting of pima S-6 failed to respond to a 10 September irrigation on Coolidge sandy loam.
    • Growth Regulator Test on Upland Cotton at the Marana Agricultural Center, 1988

      Briggs, R. E.; Nelson, J. M.; Silvertooth, Jeff; Isbell, Joan (College of Agriculture, University of Arizona (Tucson, AZ), 1989-03)
      A field study was conducted at the Marana Agricultural Center to evaluate the effectiveness of growth regulators on Deltapine 90 cotton. The Pix treatment yielded significantly higher than the check and any of the other treatments.
    • Hormonal Changes in Relation to Cutout

      Guinn, G.; Brummett, D. L.; Silvertooth, Jeff; Isbell, Joan (College of Agriculture, University of Arizona (Tucson, AZ), 1989-03)
      Experiments were conducted in 1987 and 1988 to determine whether hormonal changes may be involved in the decreases in growth and boll retention commonly referred to as cutout. Nitrogen deficiency decreased the auxin content and growth of fruiting branches. The auxin contents of fruiting branches, squares, and bolls decreased during the season as the plants entered cutout. ABA in bolls increased slightly, but the ABA content of squares and fruiting branches showed no consistent changes. The results indicate that decreases in auxin (IAA) may be involved in cutout.
    • The Influence of Sewage Sludge on Nitrogen Availability, Crop Growth, and Yield at Marana, 1988

      Ottman, M. J.; Day, A. D.; Pepper, I. L.; Taylor, B. B.; Silvertooth, Jeff; Isbell, Joan (College of Agriculture, University of Arizona (Tucson, AZ), 1989-03)
    • Irrigation Frequency During Fruiting as a Yield Determinant in Upland Cotton

      Radin, J. W.; Mauney, J. R.; French, O. F.; Silvertooth, Jeff; Isbell, Joan (College of Agriculture, University of Arizona (Tucson, AZ), 1989-03)
      When cotton is irrigated at long intervals, the root systems become less effective at absorbing water during heavy fruiting, even when the soil is moist. That ineffectiveness, if not counteracted by frequent watering can exaggerate water stress responses during fruiting and promote early cutout. Deltapine 90 cotton was grown at the Maricopa Agricultural Center in 1988 and watered either by daily drip irrigation or by level -basin flooding. In the flood-irrigated plots, various schedules for applying water during fruiting were compared with minimal differences in total water applied. The check treatment (9 postplant irrigations) yielded approximately 2 bales of lint per acre. Small supplemental irrigations on 13 July and 22 July, splitting the normal irrigation cycles, increased yield 45% for only 6% more applied water. Daily drip irrigation in the trials increased yield 63% above the check on 1% more applied water over the season. The results show that flood- irrigated yields can approach drip-irrigated yields without excessive water use, if the irrigation cycle is shortened during fruiting.
    • Late Season Boll Weevil Infestations and Survival in a Cotton Bolls in Arizona

      Henneberry, T. J.; Meng T. Jr.; Bariola, L. A.; Silvertooth, Jeff; Isbell, Joan (College of Agriculture, University of Arizona (Tucson, AZ), 1989-03)
      Studies were conducted in Phoenix AZ, to determine the development of boll weevil, Anthonomus grandis Boheman, infestations in late - season cotton bolls, the pattern of boll weevil emergence, and survival /mortality in the bolls. Boll weevils emerged from bolls buried in moist vermiculite over a period of 232 to 239 days, from 29 January to 2 August. Higher percentages of emergence and lowest mortality in bolls occurred in bolls collected in November as compared to bolls collected in December. Few boll weevils emerged from bolls held under dry conditions in an outdoor insectary for 174 days. However, an average of 16% of the weevils were found alive in the dry bolls in late May.
    • Management of Rootknot Nematode in Arizona Cotton

      Nigh, E. L. Jr.; Silvertooth, Jeff; Isbell, Joan (College of Agriculture, University of Arizona (Tucson, AZ), 1989-03)
    • Nematocide Treatment of Upland and Pima Cotton

      Farr, C.; Silvertooth, Jeff; Isbell, Joan (College of Agriculture, University of Arizona (Tucson, AZ), 1989-03)
      The loss of dying pima cotton after a rainfall in August 1987 made apparent the different responses pima and upland cottons have to stress. A trial compairing pima S-5 and DP 77 found more response of pima to treatment of rootknot nematodes with 1,3-Dichloropropene than the upland variety. A second trial found more response of DP 77 to 1,3-Dichloropropene treatment than from fenamiphos injection on sandy loam.
    • On Farm Cotton Irrigation Scheduling Management Using Infrared Thermometers in Arizona

      Garrot, D. J. Jr.; Fangmeier, D. D.; Husman, S. H.; Stedman, S.; Silvertooth, Jeff; Isbell, Joan (College of Agriculture, University of Arizona (Tucson, AZ), 1989-03)
    • Outlook on Cotton Markets and Marketing for 1989

      Firch, R. S.; Silvertooth, Jeff; Isbell, Joan (College of Agriculture, University of Arizona (Tucson, AZ), 1989-03)
    • Phosphate Sorption of Several Arizona Soils

      Silvertooth, J. C.; Gardner, B. R.; Silvertooth, Jeff; Isbell, Joan (College of Agriculture, University of Arizona (Tucson, AZ), 1989-03)
      Phosphate (P) adsorption of 6 agriculturally- important Arizona soils was studied by use of adsorption isotherm experiments and with conventional Langmuir and Freundlich adsorption models. Adsorption experiments were conducted at 25°C where each soil was placed in a 10:1 (solution:soil) ratio using 0.01M CaCl₂ as a background solution. Each soil was subjected to 4 levels of inorganic P addition using Ca(H₂PO₄)₂H₂O as the P source. Use of the Langmuir model was significant in all cases (P ≤ 0.05) with r² values ranging from 0.93 to 0.99. Capacity parameter estimates obtained from the models indicated P adsorption potentials of up to 357 lb. acre⁻¹ (818 lb. P₂0₅ acre⁻¹) for the soils studied. Application of the Freundlich model revealed r² values of 0.88 to 0.99 with all models proving to be significant (P ≤ 0.05).
    • Pima Cotton Genetics

      Percy, R. G.; Turcotte, E. L.; Silvertooth, Jeff; Isbell, Joan (College of Agriculture, University of Arizona (Tucson, AZ), 1989-03)
      Seed increase of 104 accessions and data collection on 65 accessions were obtained in 1988 to further the maintenance and evaluation of the Gossypium barbadense L. germplasm collection. In a program of conversion of tropical non flowering cottons to a day-neutral flowering habit, 63 accessions were advanced 1 generation by backcross. A systematic screening of the G. barbadense collection for bacterial blight resistance involving 200 accessions from 21 countries yielded 8 accessions resistant to races 1, 2, 7, and 18 of the pathogen. Genetic inheritance and linkage investigations of a male sterile and a foliar mutant progressed. An investigation of the geographic and taxonomic distribution of the ovate leaf trait was concluded with negative results. The frequency of the 2 mutant genes ov₁ and ov₂ proved to be too rare to yield meaningful taxonomic or geographic information about the species. Preliminary results from a performance evaluation of interspecific hybrid cottons conducted at Maricopa and Safford AZ, indicated strong environmental influences on hybrids, but generally favorable yield earliness and plant height data were obtained from the higher -elevation Safford location.
    • Pima Cotton Improvement

      Turcotte, E. L.; Percy, R. G.; Silvertooth, Jeff; Isbell, Joan (College of Agriculture, University of Arizona (Tucson, AZ), 1989-03)
      Five experimental strains, P65, P67, P64 P69, P70, and pima S-6 were grown in 9 regional tests across the pima belt in 1988. Mean yields from the 9 locations showed that P67 averaged highest in yield followed by P69, P70, P65, P68 and pima S-6 respectively. The difference in mean yield between P67, the highest yielding entry, and pima S-6 was 82 pounds of lint per acre. Pima S-6 was the latest maturing and tallest entry in the regional test at Maricopa. The 5 experimental strains had longer, finer, and whiter fiber than pima S-6.
    • The Probability of Temperature Thresholds for Defoliation

      Farr, C.; Silvertooth, Jeff; Isbell, Joan (College of Agriculture, University of Arizona (Tucson, AZ), 1989-03)
      The probability of favorable temperatures for some cotton defoliants decreases importantly in the month of October. More effective and earlier defoliation is crucial to advancing the cotton harvest to reduce rainfall damage and diapausing boll weevil numbers. Probabilities indicate more defoliation should be carried out earlier.
    • Profenofos as an Ovicide for Heliothis spp. In Short Staple Cotton and Comparison of the Ovicidal and Commercial Efficacy of Profenofos and Two Tank Mixes

      Dick, G. L.; Moore, L.; Silvertooth, Jeff; Isbell, Joan (College of Agriculture, University of Arizona (Tucson, AZ), 1989-03)
    • Progress of Upland Cotton Harvesting

      Farr, C.; Silvertooth, Jeff; Isbell, Joan (College of Agriculture, University of Arizona (Tucson, AZ), 1989-03)
      In 1984 Maricopa County produced more acres of upland cotton with lower yields than it had in 1987 but also started harvest later. Weather and insects reduced yield and early maturity of the crop; rainfall delayed harvest in the October-November period less than it had in 1987.
    • Regional Variety Test

      Pegelow, E. J. Jr.; McAlister, A. C.; Silvertooth, Jeff; Isbell, Joan (College of Agriculture, University of Arizona (Tucson, AZ), 1989-03)