• Oat Variety Trial in Cochise County, 1988

      Clark, L. J.; Schwennesen, E.; Ottman, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1988-09)
      Ten varieties of oats were grown in a trial to test grain yield. Five of the varieties produced more than 4,000 pounds per acre; the top - yielding variety, Ogle, from Minnesota, produced 4,578 pounds per acre. Difficulties in establishing a perfect stand with the small plot grain drill would probably mean that a farmer could expect yields higher than these when using full -sized equipment. Considering the premium for oats, oats for grain could be a viable alternative crop.
    • Durum Seeding Methods, 1988

      Ottman, M. J.; Harper, J.; Tickes, B.; 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 commercially available cultivars. Studies conducted at Maricopa in 1987 suggested that yields of WestBred 881 may be increased by 3-inch row spacing. Studies were conducted at three commercial farms in an effort to mimic the effect obtained with 3-inch row spacing by using conventional grain drills to obtain more uniform plant spacing. Seeding twice in parallel directions did not result in the desired effect because the seed planted in the first pass was covered by extra soil from the second pass, and the seedlings emerged from cracks made by the disk openers from the second pass. Broadcasting on beds resulted in a poor stand and non- uniform plant distribution compared to drilling the beds. Planting twice in perpendicular directions to each other resulted in a more uniform plant distribution than drilling once, but a slightly poorer stand was achieved due to extra wheel traffic and yields were not significantly increased. The best method to obtain a more uniform plant spacing may be to seed with a 3-inch drill.
    • Feed Wheat Variety and Rate of Planting Demonstration in Graham County, 1988

      Clark, L. J.; Cluff, R. E.; Ottman, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1988-09)
      Three varieties of feed wheat were compared in an on farm demonstration in the Safford valley. AC79 -97, developed by the University of Arizona for the Safford area,produced the largest amount of high protein feed Comparing 200 and 300 pound per acre seeding rates, both AC79 -97 and Super -X yielded slightly more grain at the 200 pound rate than at the 300 pound rate. Yolo, a feed wheat variety that has done well in the Sacramento valley in California, yielded slightly lower than the Super-X.
    • Oat Varieties Grown for Grain and Forage Production at the Safford Agricultural Center, 1988

      Clark, L. J.; Carpenter, E. W.; Ottman, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1988-09)
      Eleven oat varieties were tested for grain and forage yields at the Safford Agricultural Center. Cayuse, the predominant variety grown in the area was the top producer of total dry matter. Four other varieties had higher grain yields than Cayuse.
    • Barley Variety Trial in Cochise County, 1988

      Clark, L. J.; Schwennesen, E.; Ottman, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1988-09)
      Eight barley varieties were tested in a replicated variety trial in northern Cochise county. These varieties varied from relatively early maturing varieties, such as Barcot4 to the longer maturing varieties, such as Gustoe. The medium -late variety, Northrup King 1558, was the top - yielding variety, with 7,185 pounds per acre. This exceeded the yield of the standard variety, Gustoe, by 15 percent, making NK 1558 a variety that should be looked at further. It will be marketed by Northrup King under the name Sunbar 458.
    • 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.
    • Evaluation of the Accuracy of a Wheat Stem Nitrate Test in Predicting Nitrogen Requirements of Irrigated Durum Wheat

      Doerge, T.; Knowles, T.; Ottman, M.; Ottman, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1988-09)
      The procedure currently recommended by the University of Arizona for predicting the nitrogen (N) requirements of durum wheat has proven to be quite accurate at sites where grain yields exceeded 5,400 lbs/acre. However, the method slightly overestimated N needs when the yield possibility was below that level. Additional information on the relationships between N rates, stem NO₃⁻N levels and grain yields are needed for the wide range of agronomic conditions found in Arizona. Three N fertility trials were conducted at the Maricopa Agricultural Center to: 1) document the accuracy of the currently recommended soil + stem NO₃⁻N testing procedure in predicting the N needs of durum wheat on soils of varying residual N content and grain yield potentials; and 2) to evaluate the use of the current stem testing procedure on two durum varieties 'Aldura' and 'Westbred -881. The University of Arizona procedure was found to accurately predict the minimum amount of N required for optimum production of durum wheat on two sites where yield potentials were 5,400 and 4300 lbs. grain /A, but it slightly overpredicted N rates on two sites with maximum yield levels of 5,400 lbs /a. 'Aldura' consistently out yielded 'Westbred -881' by about 12 % but 'Aldura' also averaged 0.78 %lower in grain protein content. Little statistical or practical differences were observed in the quantities of NO₃⁻N contained in the stem tissue of these two varieties, which should simplify the interpretation of stem NO₃⁻N values for various wheat cultivars. The currently recommended procedure for predicting optimum N rates in durum wheat production has proven to be accurate when yield levels exceed 5,400 lbs. grain /A. A slight modification of the procedure may be needed to more closely predict N requirements on lower yielding sites.
    • Yield and Quality of Alfalfa Varieties at the Mohave Valley, 1986-1987

      Grumbles, R.; Ottman, M.; Wakimoto, V.; Ottman, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1988-09)
      Four major non - dormant alfalfa varieties were tested over 1986 and 1987. No differences in yield or quality of the varieties were determined.
    • 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.
    • Alfalfa Variety Trial in Greenlee County, 1987

      DeRosa, E.; Clark, L.; Ottman, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1988-09)
      Ten alfalfa varieties ranging from very non - dormant to moderately dominant were compared over two seasons. Significant differences were observed between yields of top varieties from 1986 to 1987. Baron, the highest yielding variety for 1986 ranked 3rd in 1987, with Valiant moving from seventh to first in 1987. Overall yields increased from seven tons in 1986 to almost eleven tons per acre in 1987. The previous county average was 5.5 ton per acre.
    • Alfalfa Varieties from the 1920s to the 1980s: Comparison of Forage Yield During the Seedling Year

      Smith, S. E.; Conta, D. M.; 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.
    • Salinity X Temperature Interactions on Germination Salt Tolerant Alfalfa

      Reffruschinni, K.; Poteet, D.; Dobrenz, A.; Cox, J.; Ottman, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1988-09)
      Continued irrigation with saline water on Arizona's already salty farm lands will increase the need for crops that are able to maintain yields under stress. We investigated responses of gemùnation salt- tolerant alfalfa (Medicago sativa L.) to salt and temperature stress interactions in comparison to Mesa - Sirsa. Significant interactions were found for the populations, salts and temperatures and their effects on percent germination. The germination salt - tolerant cycles proved to be more cold and heat tolerant under salt stress then Mesa - Sirsa.
    • Barley Response to Water and Nitrogen, 1988

      Roth, B.; Gardner, B.; Tickes, B.; Ottman, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1988-09)
      Results from 1988 show that yields of 3.9 and 3.7 tons per acre are feasible for Gustoe and NKX -1558 barley cultivars. The short season cultivar Barcott yielded about one ton less. The predicted optimum amounts of water and nitrogen were approximately 30 inches and 150 pounds per acre, respectively.
    • Timing Nematicide Application for Control of Stem Nematodes Infecting Arizona Alfalfa

      Nigh, E. L. Jr.; Ottman, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1988-09)
      The stem nematode Ditylenchus dipsaci attacks non-dormant Arizona alfalfa in the desert valleys; damage occurs during the cooler months of fall and spring. Efforts to introduce and retain resistant alfalfa has had limited success. From October until temperatures decrease below 50 F., the nematode reproduces and feeds. In warmer years, damage may be sustained from October until spring temperatures exceed 85 F. Chemical control may be warranted during these periods of feeding activity. Field trials were established to determine the efficacy of pesticides registered for use in alfalfa. Temil; Vydate, Furdan, Disyston, Thimet and Dasanit applied either in fall or spring were effective in controlling populations when first detected following dormancy. The best control is obtained when pesticides are applied immediately after harvest and prior to irrigation. Yield increases up to 15-25% were obtained with decreased yields in non -treated controls of 40-80%. Stand decline was reduced as much as 50% when treatments were correctly applied.
    • 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.
    • 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.
    • 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.
    • Revegetation of Retired Farmland: Evaluation of Six Range Grasses Under Three Irrigation Regimes

      Thacker, G.; Cox, J.; Ottman, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1988-09)
      Buffelgrass, kleingross, "Catalina" lovegrass, "Cochise" lovegrass, bottlebrush, and sideoats grama grass were seeded on retired farmland in the Avra Valley west of Tucson in 1986 and again in 1987. Each grass species was seeded in plots that received no irrigation, or two establishment irrigations or four establishment irrigations. For both year's tests, buffelgrass had a significantly higher percent cover than the other grasses at three months after planting. In the evaluation of the 1986 test in October 1987, buffelgrass, kleingrass, Cochise lovegrass, and Catalina lovegrass had increased their presence in the irrigated plots from one year before and appeared promising for the revegetaion of retired farmland. Plots that did not receive establishment irrigations did not have significantly higher cover ratings than plots with no cover at all. The one exception to this was buffelgrass in the first evaluation of the 1986 test.
    • 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.