• Corn Variety Trial in Greenlee County, 1987

      DeRosa, E.; Clark, L.; Ottman, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1988-09)
      Fifteen varieties of about 125+ day corn hybrids were tested in an ongoing variety trial in Greenlee County.
    • The Effects of Alfalfa Seed Scarification in Saline Environments

      Poteet, D. C.; Robinson, D. L.; Dobrenz, A. K.; Smith, S. E.; Ottman, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1988-09)
      The handling of alfalfa and other crop seed may result in seed scarification. Scarification may not affect germination of alfalfa seed in a non - saline environment, but may decrease germination where farmer's fields are severely salt-stressed.
    • Revegetation of Retired Farmland: Response of Fourwing Saltbush to Establishment Irrigations and Weeding

      Thacker, G.; Ottman, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1988-09)
      Fourwing saltbush (Atriplex canescens) was seeded in 80 -inch wide water harvesting microcatchments on retired farmland west of Tucson. Eight months after planting the plots that had received one establishment irrigation and weeding had significantly more cover than the unirrigated and unweeded treatments. The percent cover of the uninigated /weeded and irrigated /unweeded treatments was not significantly different. Uninigated and unweeded plots had virtually no cover of saltbush. It appears that establishing saltbush in microcatchments of this size is not feasible without either an establishment irrigation or weed control.
    • Revegetation of Retired Farmland: Response of Range Grasses to Establishment Irrigations and Microcatchment Water Harvesting

      Thacker, G.; Cox, J.; Ottman, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1988-09)
      In July 1987, an experiment was initiated to evaluate the effects of water harvesting and establishment irrigations on the establishment and persistence of buffelgrass, kleingrass, and sideoats grama grass on retired farmland A density evaluation in November 1987 revealed a significant increase in percent cover of the grasses due to establishment irrigations. No significant differences were detected among water harvesting treatments or flat- disked controls. Evaluations will continue to measure any long-term effects from these treatments.
    • Double Crop Grain Sorghum Variety Trial in Graham County, 1987

      Clark, L. J.; Cluff, R. E.; Ottman, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1988-09)
      1987 was a better year for double -crop grain sorghum than the previous year. The yields increased to nearly a ton per acre. The top - yielding variety was Asgrow Topaz at 7,885.7 pounds per acre. This yield topped the standard variety, DeKalb 64 by almost 4 percent. Bird damage was also reduced this year.
    • Bermuda Grass insect Control

      Tickes, B.; Rethwisch, M.; Ottman, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1988-09)
    • Evaluation of Plant Growth Regulators on Wheat in Arizona, 1987

      Tickes, B.; Ottman, M. J.; Ottman, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1988-09)
      Plant growth regulators are applied to small grains to decrease lodging which can adversely affect crop growth and yield. Wheat is intensively managed in Arizona, and lodging can be a problem. Chlormequat and ethephon were applied at various rates and times in six studies in 1987 to evaluate their use on Arizona's semi -dwarf cultivars with respect to lodging plant height, yield components and grain yield The results indicated that growth regulators applied at the recommended rates and times may decrease plant height and decrease kernel weight. However, the influence of growth regulator treatments on tiller number, head number, kernel number, and grain yield was not demonstrated. The ambiguous results obtained suggest our efforts need to be directed toward documenting the extent of lodging in the state, studying the effects of lodging and predicting when lodging will occur.
    • Seeding Rate and Row Spacing for WestBred 881 and Aldura Durum at Marana, 1988

      Ottman, M. J.; Day, A. D.; Ottman, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1988-09)
      WestBred 881 durum commands a premium price due to its superior quality, but it produces a lower yield than other commonly grown cultivars. This study was initiated to improve our understanding of how to grow WestBred 881. Two dumm cultivars (WestBred 881 and Aldura) were planted at five seeding rates (30, 60, 120, 180, and 240 lbs seed /A) and five row spacings (3, 6, 12, 18 an 24 inches) at the Marana Agricultural Center. The optimum seeding rate was 180 lbs /A for WestBred 881 and 120 lb /A for Aldura. An increase in seeding rate resulted in decreased kernel weight and number and increased head number. At row spacings of 3, 6 and 12 inches, grain yield of WestBred 881 was 6120, 6300, and 6060 lbs /A and grain yield of Aldura was 6350, 6770, and 7190 lb /A, respectively. WestBred 881 has larger kernels than Aldura but fewer kernels per head and heads per unit area. The yield advantage of WestBred 881 relative to Aldura at higher seeding rates was due to in kernels per head. At the closer row spacings, the advantage was due to kernel weight, kernels per head and heads per unit area.
    • The Role of Cercospora Summer Black Stem and Leaf Spot in the Alfalfa Decline Problem in La Paz County

      Matheron, M.; Winans, S.; Matejka, J.; Rethwisch, M.; Ottman, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1988-09)
      An alfalfa decline problem has appeared recently in fields between Poston and Parker in La Paz County. Cercospora summer black stem and leaf spot, a fungal disease of alfalfa, has been associated with the decline problem. The efficacy of three fungicides were tested for control of the disease and the decline problem. Bravo, Kocide, and Spotless significantly reduced the severity of Cercospora summer black stem and leaf spot; however, significant increases in yield were not realized. Alfalfa decline in La Paz County may involve other factors in addition to plant disease.
    • Effects of P Applications on Wheat Tissue Phosphate Levels and Grain Production in Graham County

      Knowles, T.; Doerge, T.; Ottman, M.; Clark, L.; Ottman, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1988-09)
      Collecting additional data to calibrate and refine current guidelines for interpreting soil and plant test values for P is an ongoing need in Arizona. An experiment was conducted at the Safford Agricultural Center during the 1987 -88 crop year to evaluate the response of 'Aldura' durum wheat to P fertilizer applications on a clay loam soil testing low in available P. Maximum grain yields of more than 5,500 lbs. /A were obtained by banding 40 lbs. P₂O₅/A as triple super phosphate with the seed at planting. A December 9 planting date subjected plants to cold soil temperatures early in the season (up to 80 days after planting), rendering soil P less available for plant utilization. Preplant soil P analyses predicted the yield increase observed with P fertilization (11.2 %);however, economic returns were not sufficient to offset the cost of P fertilizer. The recommended preplant soil test for P proved accurate in predicting P status and stem PO₄⁻P tissue analyses seemed reliable in monitoring P nutrition of durum wheat. A critical nutrient range of 1200 - 2000 ppm PO₄⁻P is proposed for basal stem tissue sampled prior to the joint growth stage, and 1500 - 1706 ppm PO₄⁻P is suggested for flag leaf tissue sampled at the boot stage.
    • Corn Variety Trial in Bonita, Cochise County, 1987

      Clark, L. J.; Schwennesen, E.; Ottman, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1988-09)
      The 1987 trials included 14 commercial corn hybrids, which were tested on a heavy - textured soil in northern Cochise county; they were the better yielding hybrids from the previous trial. Five new entries, not previously tested in Cochise county, were included. Garst 8345, one of the new entries, was both the top - yielder, at 12,499 pounds per acre, and the hybrid producing the highest adjusted gross income per acre. Hybrids produced by Pioneer, Cargill, DeKalb and NC+ seed companies all yielded more than 12,000 pounds per acre.
    • Barley Variety Trial at the Safford Agricultural Center, 1988

      Clark, L. J.; Carpenter, E. W.; Ottman, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1988-09)
      Nine varieties of barley were tested at the Safford Agricultural Center in response to growers' requests for high yielding barley varieties with the potential to mature more quickly than Gustoe. Gustoe was the top- yielding variety with 5,551 pounds per acre. A University of California variety was a close second but it has the same maturity as Gustoe. The varieties that mature more quickly, Barcott and Fiesta, yielded approximately 1,500 pounds fewer than Gustoe.
    • The Relationship Between Ten Alfalfa Varieties and the Presence of Weeds After Two Years

      Tickes, B.; Ottman, M.; Ottman, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1988-09)
    • Effect of Russian Wheat Aphid on Durum Wheat Yield

      Dick, G.; Harper, J.; Moore, L.; Ottman, M.; Ottman, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1988-09)
    • Effects of Salinity on the Water Potential of Alfalfa Seedlings

      McKimmie, T.; Dobrenz, A. K.; Ottman, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1988-09)
      Alfalfa seedlings were grown under saline conditions for six weeks and separated into two populations, based on height. Water potential was measured on roots, stems, leaves, and petioles of tall and short plants. Tall plants had a higher water potential for each plant part.
    • Development of Grazing-tolerant Alfalfa for the Southwest

      Smith, S. E.; Rodrigues, G. H. S.; Conta, D. M.; McKinley, L.; Ottman, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1988-09)
    • Stomate Density and Physiological Measurements on Leaves of Alkali Sacaton

      Dobrenz, A. K.; Cox, J.; Munda, B.; Robinson, D.; Ottman, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1988-09)
    • Comparison of Residual Nitrate and Fertilizer Nitrogen Efficiency in Basin Irrigated Wheat

      Doerge, T.; Knowles, T.; Ottman, M.; Clark, L.; Ottman, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1988-09)
      The relative efficiencies of residual soil NO₃⁻N and fertilizer Nin basin - irrigated wheat production are not well defined. A two-year field study was conducted at the Safford Agricultural Center to investigate what these N efficiencies are under optimum yielding conditions. 'Aldura' durum wheat was grown on the same field site two years in succession. In 1987 a wide range of fertilizer N (0 to 419 lbs /A) applications resulted in residual NO₃⁻N accumulations of 36 to 140 lbs /A in the surface four feet of soil. Residual N plots were split in 1988 with one subplot receiving no additional N while the other was treated with 145 lbs of fertilizer N /A. Grain yield response curves for the –N and +N subplots were used to estimate the marginal rate of substitution (MRS) of soil NO₃⁻N for fertilizer N. The marginal efficiency of residual NO₃⁻N was a constant 16.7 lbs. grain produced /lb. of N across the range of profile N values in this study, while the marginal efficiency of fertilizer N varied from over 17 to below 6 lbs. grain /lb. N. When basin- irrigated wheat is supplied with adequate, but not excessive N, the MRS of soil vs. fertilizer N is about 1:1 although absolute N efficiencies under basin irrigation are considerably lower than those achieved in other grain production systems.
    • Breeding Strategies for Alfalfa Grown Under Saline Conditions

      Johnson, D. W.; Smith, S. E.; Dobrenz, A. K.; Ottman, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1988-09)
    • Alfalfa Variety Demonstration at the Safford Agricultural Center, 1984-87

      Clark, L. J.; Cluff, R. E.; Ottman, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1988-09)
      Twenty non - and very non - dominant alfalfa varieties were compared over three seasons. The top - yielding variety, Pioneer 5929, has maintained this position for the last three years. The yields decreased considerably from the previous year, however. Part of the loss can be attributed to the sacrifice of the first cutting because of damage by the Egyptian alfalfa weevil. Pioneer 5929 was the top -yielding variety during the entire trial, producing more than 30 tons per acre. Four other varieties produced more than 28 tons per acre: Ardiente by Agripro; Pierce by Northrup King, Palmer Special by the Palmer brothers of Graham county; and Safford 80 LH.