• Intercropping Studies with Different Cereal and Legume Crops

      Menezes, Eduardo; Voigt, Robert; Ottman, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1986-09)
      An intercropping study was carried out with three legumes (field beans, cowpeas, and soybeans) and three cereals (sorghum, corn, and pearl millet) in all combinations to define the most appropriate intercropping under near optimum irrigation. The sorghum x soybean intercropping was chosen as the most appropriate for the environment.
    • Determining the Economic Damaging Level of the Egyptian Alfalfa Weevil Hypera brunneipennis (Bohemian)

      Cotty, Susanne; Ottman, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1986-09)
      An experiment was conducted to ascertain the population level of Egyptian alfalfa weevil Hvpera brunneipennis (EAW) at which chemical control becomes economically justified. Four treatments were established by applying malathion at 1 lb. a.i./acre when an average of 5,10,15, or 20 weevil larvae were found per five sweeps; one treatment was sprayed every week (0 larvae) and the controls received no chemical treatment. Five 180- degree sweeps were taken weekly in each plot with a standard 15 -inch net and net contents were emptied into a white plate for counting. EAW larvae and adults were counted and insecticide was applied when the larval number reached the designated level. Hay from each plot was cut twice manually, air dried and weighed. Significant yield differences (P =0.05) occurred between the 0 larvae treatment and the other treatments for the first cutting but no yield differences occurred for the second cutting.
    • Seeding Rate of One-Irrigation Barley

      Ottman, Mike; Ramage, Tom; Thacker, Gary; Ottman, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1986-09)
      One-irrigation barleys have been selected for performance with a pre-plant irrigation to fill the soil to field capacity to a depth of 5 feet. The barley is then grown with no additional irrigation, which simulates conditions of the North African coast. In this study, two of these barley selections were planted at four planting rates at three dates in Marana to determine optimum seeding rates. A seeding rate of 20 lbs /A resulted in greater yields than 40, 60, or 80 lbs /A when the data were combined for all planting dates.
    • Crop Yield Variability in Irrigated Wheat

      Husaker, Douglas; Bucks, Dale; Ottman, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1986-09)
      Optimum design and management of irrigated wheat production is limited by the scarcity of information available on yield variability. The purpose of this study was to evaluate the spatial variability in soil-water parameters and the effects compared to grain yield response under level-basin irrigation. Three levels of seasonal irrigation water and two border lengths were used. Grain yields were found to increase significantly with the amount of water applied and soil water depletion (estimate of crop evapotranspiration), although yield variability was greater with reduced or deficit irrigations. Variations in soil water content were responsible for about 22% of the variability in grain yield, indicating that other soil and crop- related factors had a significant influence on production. Spatial dependence was exhibited over a greater distance at the wetter compared with the drier irrigation regimes.
    • Durum Wheat Variety Trials, Cochise County - 1986

      Clark, Lee; Ottman, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1986-09)
    • Water Use Variability in Irrigated Wheat

      Bucks, Dale; Hunsaker, Douglas; Ottman, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1986-09)
      An understanding of the expected variability in irrigated crops under field size, surface irrigation conditions is needed to improve irrigation designs and water management scheduling procedures. The objective of this work is to describe water application uniformity under an efficient level -basin irrigation system and the variability of water use (soil water depletion) for three levels of irrigation and two basin lengths for a wheat crop. High water distribution uniformities with a level -basin irrigation system did not necessarily result in maximum irrigation application efficiencies where variations in soil -water factors were greater on a drier irrigation treatment than medium or wet treatment. Variations in soil water depletion were found for all irrigation treatments with the largest variation (13 %) occurring for the drier treatment. Spatial dependence was exhibited for soil water depletion but not necessarily for seasonal irrigation water applications.
    • Summary of 1986 Wheat and Barley Variety Trials in Yuma, Poston and the Mohave Valley

      Ottman, Mike; Tickes, Barry; Winans, Sherwood; Grumbles, Robin; Ottman, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1986-09)
    • Specific Leaf Weights: Daily Trends in an Alfalfa Field

      Robinson, David; Dobrenz, Albert; Ottman, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1986-09)
    • Improving the Germination Salt Tolerance of Alfalfa

      Dobrenz, Albert; Robinson, David; Smith, Steve; Ottman, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1986-09)
      The development of alfalfa that can germinate at extremely high NaC1 levels will improve early emergence and establishment of this important forage crop in saline soils. We have identified plants in the eighth cycle of selection that germinated at -3.0 MPa (30,000 ppm). Seed from these plants displayed a 40% better germination at -2.1 MPa (21,000 ppm) than the previous cycle. Germination at higher salt concentrations were not different between the two germplasm sources.
    • Small Grain Variety Comparisons at the Yuma Agricultural Center in 1986

      Thompson, Rex; Bobula, Jamie; Ottman, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1986-09)
    • Response of Guar to Drought Conditions

      Ray, Dennis; Livingston, Margaret; Ottman, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1986-09)
      Plants with greater drought tolerance will increase crop production in many areas of the world. The purpose of this study was to examine the physiological responses of guar, a drought tolerant plant, under water stress. The dry treatment received only one irrigation and yielded respectably. This treatment maintained turgor and metabolic functions throughout the study by decreasing transpiration rate and increasing diffusive resistance.
    • Will Dryland Farming Be Feasible in the Avra Valley?

      Thacker, Gary; Ottman, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1986-09)
    • Grain Sorghum Production in South-Central Arizona. III: Double Crop, Rainfed - 1985

      Voigt, Robert; Schmalzel, Carl; Ottman, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1986-09)
      Seventy-two commercial hybrid grain sorghums representing 17 commercial sources were grown for grain in a late planted, simulated double-crop after barley or wheat harvest. The test, grown at the University of Arizona Marana Agricultural Center, was planted in a pre-irrigated seed bed, but was rainfed thereafter. Grain yields ranged from a high of 3420 lbs/acre down to a low of 1750 lbs/acre.
    • Grain Sorghum Production in South-Central Arizona. I: Full Season, Full Irrigation - 1985

      Voigt, Robert; Schmalzel, Carl; Ottman, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1986-09)
      Seventy-two commercial hybrid grain sorghums, representing 20 commercial sources, were grown full season for grain yield with irrigation water applied as necessary to prevent moisture stress. The test, grown at the University of Arizona Marana Agricultural Center, had grain yields ranging from a high of 6375 lbs/acre down to 3292 lbs/acre.
    • Predicting the Nitrogen Needs of Wheat Using Stem Nitrate Analysis

      Doerge, Thomas; Ottman, Mike; Ottman, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1986-09)
      The high yielding spring wheats grown in Arizona usually require applications of fertilizer nitrogen (N) to achieve optimum yields and acceptable quality. The University of Arizona's currently recommended procedure of preplant soil plus periodic stem tissue analysis for NO₃-N to predict the N needs of wheat is not widely used by Arizona growers. A nitrogen fertility trial was conducted at the Maricopa Agricultural Center during the 1985-86 crop year to evaluate the accuracy and practicality of the currently recommended procedure for predicting the optimum N rate for 'Aldura' durum wheat grown on a sandy soil low in residual N. Five rates of N from 0 to 500 lbs N/a were applied in four split applications. Three additional N treatments were made using equivalent amounts of three different N sources (urea, ammonium nitrate, and calcium nitrate) as indicated by the current UA procedure. Maximum grain yields of over 6500 lbs/a and protein levels above 13% were attained with the application of 215 to 250 lbs Nia. The amount of N predicted by the UA procedure (215 lbs N/a) did attain maximum grain yield and resulted in the most favorable adjusted economic return of all the fertilizer treatments used in the trial. Though additional work is needed, the stem NO₃-N tissue test was practical to use and proved quite accurate in predicting the N needs of durum wheat.
    • Alfalfa Hay Quality and Dairy Nutrition

      Zaugg, Ned; Ottman, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1986-09)
      Alfalfa may be harvested and used as green feed, pellets, haylage, cubes, hays or matured for seed. The value of the product is determined in part by the yield, costs of production, demand and end usage. The high nutrient composition makes this feed a major component of balanced rations. However, its quality is highly variable from production through harvest, storage and feeding.
    • Barley Variety Test at Rayner Bros, Goodyear, AZ - 1985-86

      Dawson, Lester; Ottman, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1986-09)
    • Drought Tolerance in Pearl Millet

      Osman, Mohamoud; Dobrenz, Albert; Tewolde, Haile; Voigt, Robert; Ottman, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1986-09)
    • Full Season Grain Sorghum Variety Trial, Greenlee County - 1985

      DeRosa, Edith; Clark, Lee; Parsons, David; Ottman, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1986-09)
    • Grain Sorghum Production in South-Central Arizona. II: Full Season, Limited Irrigation - 1985

      Voigt, Robert; Schmalzel, Carl; Ottman, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1986-09)
      Seventy-two commercial hybrid grain sorghums representing 17 commercial seed companies were grown full season for grain yield with limited irrigation for medium moisture stress. The test, grown at the University of Arizona Marana Agricultural Center, had grain yields ranging from a high of 5098 lbs/acre down to 2100 lbs/acre.