• Response of Alfalfa to Phosphorus Fertilizer Sources

      Stroehlein, Jack; Clark, Lee; DeRosa, Edith; Ottman, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1987-09)
      A field study was carried out to determine the effects of different fertilizers on yield and quality of alfalfa. Two harvests over a period of four cuttings did not reveal any differences due to treatment. While alfalfa often responds to phosphorus (P) fertilizer application, conditions in this study provided adequate P as well as nitrogen (N) and potassium (K).
    • Response of Barley and Wheat to Sewage Sludge Loading Rates

      Day, Arden; Solomon, Mengste; Taylor, Brooks; Pepper, Ian; Minnich, Martha; Ottman, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1987-09)
      A greenhouse experiment was conducted to evaluate the responses of barley and wheat to sewage sludge loading rates of 150 to 750 lb /acre plant-available N and to recommended inorganic N (150 lb/ acre). All sewage sludge rates delayed maturity in both barley and wheat. Sludge loading rates up to 450 lb /acre of plant-available N increased vegetative growth and grain yield in both crops. Sludge rates higher than 450 lb/acre of plant-available N resulted in a reduction in the number of plants per pot; however, the stand reduction was greater for wheat than for barley.
    • Russian Wheat Aphid, Diuraphis noxia (Mordvillko): A New Insect Pest of Small Grains in Arizona

      Dick, Gary; Moore, Leon; Ottman, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1987-09)
    • Salt Tolerance During Seedling Establishment in Alfalfa

      McKimmie, Tim; Dobrenz, Albert; Ottman, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1987-09)
      Deposition of salts from irrigation water is an increasing concern for Arizona farmers and agronomists. Selection for salt tolerance during the seedling stage has been undertaken over the past three years. Yield tests were conducted in greenhouses and a significant increase in dry matter production was shown in the selected material.
    • Seeding Rate and Row Spacing for Westbred 881 and Aldura Durum Wheat at Maricopa, 1987

      Ottman, Mike; Day, Arden; Harper, John; Ottman, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1987-09)
      Westbred 881 durum wheat commands a premium price due to its superior quality, but produces a lower yield than other commonly grown commercial cultivars. This study was initiated to improve our understanding of how best to manage Westbred 881. Two durum wheat cultivars (Westbred 881 and Aldura) were planted at 5 seeding rates (30, 60, 120, 180, and 240 lbs. seed/A), 5 row spacings (3, 6, 12, 18, and 24 inches), and two planting dates (Dec. 1 and Jan. 16) at the Maricopa Agricultural Center. Both cultivars produced optimum yields at seeding rates of 120 to 180 lbs/A for the Dec. 1 planting date. At the Jan. 16 planting date, however, yields of Westbred 881 increased linearly with seeding rate up to 240 lbs/A, while Aldura produced optimum yields between 120 and 180 lbs. seed/A. At the Dec. 1 planting date, Aldura produced similar yields at row spacings from 3 to 12 inches, while the yield of Westbred 881 decreased linearly with an increase in row spacing. The highest yield achieved in this study was with Westbred 881 at the 3 -inch row spacing. Row spacings of 6 to 12 inches were optimum for both Westbred 881 and Aldura at the Jan. 16 planting date. The seeding rate and row spacing responses attained with Westbred 881 may be related to its tittering characteristics.
    • Seeding Rate, Nitrogen Rate, and Planting Date of One-Irrigation Barley at Marana, 1987

      Ottman, Mike; Ramage, Tom; Thacker, Gary; Ottman, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1987-09)
      One-irrigation barleys were bred to be grown with only a single irrigation near planting time. To further our understanding of how to manage these new cultivars, one-irrigation barleys were grown at 4 seeding rates (20, 40, 60, and 80 lbs seed /A), 4 nitrogen rates (0, 50, 100, and 150 lbs/A), and 3 planting dates (Nov. 17, Dec. 15, and Jan. 22). Seeding rates 01 40 to 60 lbs seed/A resulted in the highest yields at the Dec. 15 planting date, comparing all planting dates combined. However, in individual analyses of the Nov. 17 and Jan. 22 planting dates, no significant differences in yield due to seeding rate were detected. Grain yield increased linearly with nitrogen rate at the Nov. 17 planting date, but was not influenced by nitrogen rate at the other planting dates. Yields were similar for the Nov. 17 and Dec. 15 planting dates, but decreased considerably in the Jan. 22 planting date due partially to lower head number. Grain yields of 2-22-9 were consistently higher than Seco this year.
    • Seedling Alfalfa Root Research

      Reffruschinni, Katie; Robinson, David; Dobrenz, Albert; Ottman, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1987-09)
      There has been limited research on the rooting patterns of alfalfa. This information would be important in developing new germplasm sources that are more water efficient, salt tolerant and drought tolerant. Ten alfalfa varieties were evaluated for possible genetic control of rooting traits. Seedlings were grown hydroponically in a growth chamber. The cultivars evaluated showed a significant statistical difference for width of lateral root system and number of lateral roots. The variation in seedling rooting patterns is sufficient to warrant a selection program for improved lateral rooting patterns.
    • Small Grain Comparisons at the Maricopa Agricultural Center in 1987

      Thompson, Rex; Sheedy, Michael; Ottman, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1987-09)
    • Small Grain Variety Comparisons at the Yuma Agricultural Center in 1987

      Thompson, Rex; Sheedy, Michael; Ottman, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1987-09)
    • Standardization of the Wheat Stem Tissue NO₃-N Procedure

      Knowles, Tim; Doerge, Thomas; Ottman, Mike; Ottman, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1987-09)
      Current University of Arizona recommendations require periodic stein NO₃-N tests to determine nitrogen (N) fertility status of wheat crops. Lack of data on the importance of sample handling techniques, plant part selection, grinding criteria and extraction conditions have resulted in a reluctance by some growers and laboratory operators to utilize this test procedure. A laboratory study was carried out to examine factors important in wheat stem tissue analysis for NO₃-N. Sample handling, fineness of tissue grinding, and different extraction ratios were examined to determine their effects on NO₃-N recovery. Detailed partitioning of wheat plants at the 3-4 leaf, joint and boot growth stages was conducted to document which plant part is the best indicator of the N status of wheat. Optimal recovery of tissue NO₃-N existed for stem tissue separated immediately in the field and dried within 8 hours; stem tissue ground to 30 mesh or less and extracted for at least 30 minutes; and when using a sample size of 0.1000 g, in conjunction with 25 ml of extractant (i.e. 1:250 plant tissue to extractant ratio). Partitioning data confirmed current University of Arizona wheat tissue sampling guidelines which suggest sampling of the basal portion of the stem tissue.
    • Stomatal Response to Water Stress in Two Pearl Millet Genotypes

      Osman, Mohamoud; Dobrenz, Albert; Tewolde, Haile; Voigt, Robert; Ottman, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1987-09)
      A study was conducted in the field to test whether stomatal sensitivity to water stress can be used as a selection criterion for drought tolerance in two pearl millet genotypes. In both cultivars, stomatal aperture was significantly reduced by the water stress. However, the proportion of reduction per 20 mm decrease in applied water was much higher for the hybrid than for the female parent. This is clearly an indication of a higher stomatal sensitivity in the hybrid, which probably explains the superior performance under water stress that was previously observed in this genotype.
    • Strain Crossing for Large-Leaflet Alfalfa: A First Look

      Dobrenz, Albert; Robinson, David; Smith, Steve; Ottman, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1987-09)
    • Summary of Commercial Hybrid Grain Sorghum Yield Tests at Marana, 1983-85

      Ottman, Mike; Voigt, Robert; Schmalzel, Carl; Ottman, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1987-09)
    • Water Stress Indices for Research and Irrigation Scheduling in Pearl Millet

      Teowolde, Haile; Voigt, Robert L.; Osman, Mahamoud; Dobrenz, Albert K.; Ottman, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1987-09)
      The capability to measure the magnitude of water stress in plants is useful for precision irrigation scheduling and other purposes. This paper reports an evaluation of leaf (TL) and canopy (Tc) temperatures, leaf minus air (TL -Ta) and canopy minus air (Tc -Ta) temperatures, and leaf water stress index (LWSI) and crop water stress index (CWSI) in detecting stress in pearl millet (Pennisetum americanum (L.) Leeke) over two growing seasons. Baselines which were used to compute LWSI and CWSI were obtained. The upper and lower baselines for the Tc data, respectively, were Tc -Ta = 4.10 C and Tc -Ta = 3.87- .2001VPD where VPD is vapor pressure deficit in mbars. For the TL data, the upper and lower baselines, respectively, were TL -Ta = 1.97oC and TL -Ta = 1.308- .03006VPD. Tests against photosynthesis, transpiration, and grain yield showed that LWSI and CWSI are better indices of stress than TL -Ta, Tc -Ta, TL, Tc, or Ta. Average seasonal LWSI and CWSI ranged from approximately 0.03 for non- stressed to 0.80 for stressed plants. The reliability of LWSI and CWSI to detect stress and their relation with grain yield suggested the possibility of using these indices for irrigation scheduling decisions.
    • Wheat and Barley Variety Test at the Bruce Church Range, Poston, 1987

      Winans, Sherwood; Ottman, Mike; Ottman, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1987-09)
      A wheat and barley test on the Bruce Church Ranch, Poston, Arizona, La Paz County, harvested June 8 & 9, 1987, gave crop and variety performance differences under grower management conditions. The top yielding barley variety was Fiesta, 6990 lbs /ac. The leading durum varieties were Turbo, Gem and Aldura. Durum wheat Westbred 881 was highest in protein (13.7 %). In red wheat varieties, yields ranged from 4660 to 5750 lbs/ac. The top three varieties were Baker, Probred and Yecora Rojo. Baker was highest in protein (14.6 %), followed by Yecora Rojo (14.2%). Continued testing over several years is necessary to assess variety performance under grower management conditions.
    • Wheat Germplasm Releases by the Agricultural Experiment Station in 1987

      Thompson, Rex; Ottman, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1987-09)
    • Wheat Variety Demonstration in Roll, 1987

      Tickes, Barry; Ottman, Mike; Ottman, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1987-09)
    • Wheat, Barley and Oats for Forage and Grain Production at the Yuma Valley Agricultural Center, 1986-87

      Tickes, Barry; Ottman, Mike; Ottman, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1987-09)
      The potential of various types of small grains for winter forage production was investigated in this study. Two varieties of red wheat, durum wheat, barley, and oats were harvested at various stages. Harlan if barley produced the most forage at the early cutting while Mesa oats yielded the most forage at the later cutting. Gustoe barley produced the highest grain yields.
    • Winter Wheat Variety Trial in Cochise County, 1987

      Clark, Lee; Ottman, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1987-09)
      Sixteen winter wheat varieties (including three hybrids) were evaluated in a randomized, complete block experiment, with four replications. Stephens, the standard variety grown in the area, was outyielded by four of the winter wheat cultivars, including two of the hybrids. The highest yielding cultivar was a hybrid, Bounty 100, which yielded 5853 pounds per acre (23% higher than Stephens).
    • Yield and Water Use of Barley Cultivars Compared Under an Irrigation Water Gradient at Marana, 1987

      Ottman, Mike; Ramage, Tom; Brown, Paul; Thacker, Gary; Ottman, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1987-09)
      This study was initiated to determine how barley cultivars perform outside the environment for which they were selected. Also, a comparison was made of water use by a one-irrigation barley with water use of a commercial cultivar selected for high yield conditions. Six barley cultivars bred for differing growing conditions (Westbred Gustoe and Westbred Barcott - high input; Arivat and Prato - medium input; and, Seco and 2-22-9 - low input) were compared under 12 water regimes delivered by a line -source sprinkler system. Water use of Seco, a one-irrigation barley, and Westbred Gustoe, a commercial barley, was monitored with a neutron probe. The barley cultivars bred for high, medium, and low input conditions performed best in their respective optimum water levels with the exceptions of Westbred Barcott and Prato. Westbred Barcott (high input) yielded relatively well over all water levels, and Prato (medium input), performed similar to a high input barley. Seco (low input) used slightly less water than Westbred Gustoe (high input), primarily due to its earlier maturity. The water extraction pattern with depth was similar for both cultivars due to the frequent shallow irrigations applied in this study. The water extraction pattern of Seco needs to be investigated under one- irrigation conditions.