• 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)
    • 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)
    • 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)
    • Response of Texas Root Rot to an Application of a Soil Sterilant in Marana, 1988

      Thacker, Gary; Silvertooth, Jeff; Silvertooth, Jeff; Isbell, Joan (College of Agriculture, University of Arizona (Tucson, AZ), 1989-03)
      Methyl bromide/chloropicrin (MB/C), a soil sterilant, was deep injected into cotton beds 6 days before planting in 1988. Application rates were zero, 300, 400, and 500 pounds of MB/C per acre, injected 18-inches deep into the sandy loam soil. Short staple lint yields in all of the MB/C treatments were significantly higher than the untreated check. MB/C at all application rates was 100% effective in preventing the plants from dying from the disease, while 86% of the plants in the untreated check plots died.
    • Short Staple Variety Demonstrations, Pinal County

      Malcuit, J.; Stedman, S.; Silvertooth, J.; Silvertooth, Jeff; Isbell, Joan (College of Agriculture, University of Arizona (Tucson, AZ), 1989-03)
    • Tierra Prospera Farms CWSI Irrigation Scheduling Demonstration Test

      Garrot, D. J. Jr.; Stedman, S.; Benedict, D. B.; Silvertooth, Jeff; Isbell, Joan (College of Agriculture, University of Arizona (Tucson, AZ), 1989-03)
    • 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)
    • Regional Variety Test

      Pegelow, E. J. Jr.; McAlister, A. C.; 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.
    • Response of Cotton to Various Fertilization Histories

      Hofmann, W. C.; Else, P. T.; Silvertooth, Jeff; Isbell, Joan (College of Agriculture, University of Arizona (Tucson, AZ), 1989-03)
      Effects of various fertilization histories on cotton yield were investigated for the fourth consecutive year in the same field at the Maricopa Agricultural Center. Treatments included: 1) no fertilizers added for the past 4 seasons, 2) aggressive nitrogen fertilization in the 1988 season, no fertilization for the previous 3 seasons, 3) standard nitrogen fertilization in 1988 similar treatment for the previous 3 seasons, 4) aggressive nitrogen fertilization in 1988 same history as treatment #3 for previous 3 seasons, and 5) a commercial alternative fertilization program (BioHumaNetics, Inc.). Yields in 1988 were significantly different with treatment 2 having the highest yield followed by treatments 3 and 4, followed by treatment 5; treatment 1 had the lowest yield.
    • Response of Cotton to a Preplant Zinc Sulfate Application

      Hofmann, W. C.; Else, P. T.; Silvertooth, Jeff; Isbell, Joan (College of Agriculture, University of Arizona (Tucson, AZ), 1989-03)
      The effect of a single preplant application of zinc sulfate on DPL 77 yield was investigated at the Maricopa Agricultural Center on a field that had tested as marginal with respect to zinc availability. No significant difference in yield was found between the plants receiving zinc sulfate and the control.
    • Cotton Response to Water and Nitrogen, 1988

      Roth, R. L.; Gardner, B. R.; Silvertooth, Jeff; Isbell, Joan (College of Agriculture, University of Arizona (Tucson, AZ), 1989-03)
      Water - nitrogen production functions were determined for cotton cultivars, DPL 77 and DPL 90. Cotton yields for the DPL 90 cultivar were reduced more than the DPL 77 cultivar when water applications were reduced. Cotton yields of 3.0 to 3.4 bales/acre were predicted for nitrogen applications of 160 to 210 lbs/acre with appropriate water applications.
    • The 1989 Upland Cotton Program: How Profitable for Arizona Producers?

      Ayer, H. W.; Silvertooth, Jeff; Isbell, Joan (College of Agriculture, University of Arizona (Tucson, AZ), 1989-03)
      The profitability of full and "50/92" participation in the 1989 upland cotton program was estimated for representative farms in Maricopa, Pinal, LaPaz and Yuma counties. Special attention was given to the effect on profits of the reduction in permitted acreage, and to farm size and multiple-partner ownership. Full participation was more profitable than "50/92" or nonparticipation given the assumptions used here. The expected profitability of the crops used on 'free acres" in the large farm case -- alfalfa or pima cotton --has a major positive effect on program profitability. The possible use of upland base acres to produce pima cotton or durum wheat, given the current high prices of those crops, is also discussed.
    • Strategies to Capture Higher Gross Revenues

      Firch, R. S.; Silvertooth, Jeff; Isbell, Joan (College of Agriculture, University of Arizona (Tucson, AZ), 1989-03)
      Research on futures price behavior indicates that farmers may find it feasible to use selective hedging or forward contracting to increase gross receipts from the sale of their commodities. University economists have been telling farmers for many years that selective hedging-hedging only in some years rather than all years or no years -- should not be considered as an alternative to hedging every year or never hedging. If selective hedging is to be a feasible strategy for farmers, they must have some system for correctly predicting the direction of futures price changes during the production period in most years.
    • 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).
    • Can Cotton (Cossypium hirsutum) Seed Vigor Be Assessed in the Absence of Growth?

      Lehle, F. R.; Zegeer, A. M.; Silvertooth, Jeff; Isbell, Joan (College of Agriculture, University of Arizona (Tucson, AZ), 1989-03)
      Although seed vigor is ultimately expressed in terms of growth, it is not clear if metabolic processes unlinked to growth can also estimate vigor. The objective of this study was to determine if the relationship between seed vigor and ethanol metabolism differed depending on whether seed growth was presence or absence. For individua1 imbibed cotton seed, ethanol assimilation in air and ethanol biosynthesis in N₂ gas was correlated to seed vigor as measured by cool test performance. Seed growth in N₂ gas was prevented by the addition of polyethylene glycol. Results were inconclusive, because seed performance (radicle growth) during cool testing was not significantly correlated to either ethanol biosynthesis or ethanol assimilation. It was concluded that ethanol metabolism both in the absence and presence of seed growth has limited usefulness as a metabolic marker of cotton seed vigor.
    • Effects of Banded Phosphorus Fertilizer on Cotton

      Silvertooth, J. C.; Doerge, T. A.; Thacker, G. W.; Stedman, S. W.; Malcuit, J. E.; Silvertooth, Jeff; Isbell, Joan (College of Agriculture, University of Arizona (Tucson, AZ), 1989-03)
      Four field experiments were established in 1988 in Arizona to evaluate the effects of banded phosphorus (P) fertilizers on cotton. 2 sites involved upland cotton (Gossypium hirsutum L.) and 2 sites with pima (G. barbadense L. var Pima S-6), with 1 of each located near Marana, AZ (Vinton Anthony sandy loam). A site with 1 of each kinds was also located near Coolidge, AZ (Mohall sandy loam). At the Marana studies, P was applied 6 inches directly below the zone of seed placement at the time of listing and at the Coolidge sites, P was applied 6 inches below and 2 inches to the side of the zone of seed placement after listing but before planting. In all cases, the P source was 10-34-0 at rates of 0, 30, and 65 lb. P₂O₅ acre⁻¹. At the Marana location, a treatment of banded 10-34-0 at 30 lb. P₂O₅ acre⁻¹ plus a foliar application of 10 lb. P₂O₅ acre⁻¹ (early bloom) as 10-34-0 was included in both the upland and the pima experiments. Plant measurements for plant height, flower numbers, node numbers, boll numbers, and nodes to first fruiting branch were taken to evaluate plant response throughout the season. Plant tissue samples were also taken for leaf petiole PO₄-P and leaf blade total P analysis. Lint yield measurements were also taken. No statistically significant (P < 0.05) differences were found among any of the treatments for any of the measured parameters, except in the petiole PO₄-P levels from the upland study at Coolidge on the second sampling date.
    • Soil Amendments on Cotton, Safford Agricultural Center, 1988

      Clark, L. J.; Carpenter, E. W.; Silvertooth, Jeff; Isbell, Joan (College of Agriculture, University of Arizona (Tucson, AZ), 1989-03)
      Cotton was grown in the fourth year of a soil amendment trial that evaluated 4 different soil amendments in 12 treatments on the Safford Agricultural Center. Yields varied from 1,659 to 1,392 pounds of lint per acre but none of the treatments yielded statistically different from the check. The higher yields were seen in the treatments with high and medium rates of soil sulfur, Boligrow, or gypsum, the lower yields were seen in the treatments with low rates of those amendments or with a biological amendment, but the conclusion of the study is that soil amendments did not significantly increase yields on that soil with its EC value of 2.3 dS/m. Crop and fiber quality measurements are reported here.
    • Response of Pima Cotton to Zinc Fertilization in Pima County, 1988

      Silvertooth, J. C.; Thacker, G.; Doerge, T. A.; Silvertooth, Jeff; Isbell, Joan (College of Agriculture, University of Arizona (Tucson, AZ), 1989-03)
      A single field experiment was conducted near Marana, AZ, in 1988 to evaluate the effects of both soil - and foliar- applied zinc (Zn) fertilizers on the yield of pima cotton. The soil had a preseason level of 0.6 ppm Zn (DTPA extractable). Treatments included 10 lbs. Zn acre⁻¹ (as ZnSO₄) broadcast incorporated preplant, 0.5 lbs. Zn acre⁻¹ applied as a foliar treatment at early bloom, and a treatment consisting of both the soil and foliar Zn applications. Yield results revealed no differences among any of the treatments in comparison to one another, or the check treatment.
    • Effect of Plant Nitrogen Status and Growth Regulators on Earliness, Effectiveness of Defoliants, and Yield of Upland Cotton

      Nelson, J. M.; Briggs, R. E.; Hart, G.; Silvertooth, Jeff; Isbell, Joan (College of Agriculture, University of Arizona (Tucson, AZ), 1989-03)
      A field study was conducted at the Maricopa Agricultural Center to determine the effect of nitrogen fertility level and growth regulators on earliness, yield of cotton, and effectiveness of defoliants. Nitrogen application rates of 80, 120 and 160 lbs N/A did not influence lint yields or the response of cotton to growth regulators. The growth regulator Piz tended to promote earliness but did not affect final yield. The defoliants tested achieved good leaf drop results independent of the plant nitrogen status. Petiole nitrate-N content at the time of defoliation (4 October) did not correlate well with the response of cotton to defoliation treatments.