• Small Grains Variety Evaluation at Arizona City, Maricopa and Yuma, 2013

      Ottman, M. J.; Ottman, Michael J.; School of Plant Sciences / Maricopa Ag Center, University of Arizona (College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2013-05)
      Small grain varieties are evaluated each year by University of Arizona personnel. The purpose of these tests is to characterize varieties in terms of yield and other attributes. Variety performance varies greatly from year to year and several site-years are necessary to adequately characterize the yield potential of a variety. A summary of small grain variety trials conducted by the University of Arizona can be found online at http://ag.arizona.edu/pubs/crops/az1265.pdf.
    • Cultivar and Nitrogen Effects on Yield and Grain Protein in Irrigated Durum Wheat, 2012

      Wang, Guangyao (Sam); Brunson, Kevin; Thorp, Kelly; Ottman, Mike; Ottman, Michael J.; School of Plant Sciences / Maricopa Ag Center, University of Arizona; Arid-Land Ag Research Center, USDA-ARS, Maricopa, AZ (College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2013-05)
      The grain yield and nitrogen use efficiency of durum wheat vary in response to genotypic and nitrogen fertilization were studied in field during two growth seasons. The aim of this study was to evaluate the effects the N fertilizer rate on grain yield and quality under irrigated desert conditions in relation to N utilization. Six durum wheat cultivars (Duraking, Havasu, Kronos, Ocotillo, Orita, Topper) were grown in field trails under irrigated regimes at five N levels (0, 65, 110, 160, 240 lbs/acre) in 2010-2011 and six N levels (0, 65, 110, 160, 240, 360 kg ha-1) in 2011-2012 at Maricopa Ag Center. The results showed the varieties and N levels both significantly affected grain yield, grain protein concentration, and nitrogen use efficiency. A simple and rapid method to measure crop N status using SPAD meters was also developed. The results showed that using the differences in SPAD readings between the first and second fully expanded leaves is a useful way to improve effectiveness of SPAD meters in durum wheat N management.
    • 2012 Sorghum Silage Variety Trial at Maricopa

      Loper, Shawna; Ottman, Mike; Ottman, Michael J.; School of Plant Sciences / Maricopa Ag Center, University of Arizona (College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2013-05)
      Nine varieties of silage sorghum and one pearl millet variety were tested at the Maricopa Agricultural Center in Maricopa, AZ. Information on silage sorghum yield and quality can be of use to the dairy industry and help growers choose the best varieties based on their needs. We found no significant differences among the varieties for ash, ADF, and NDF. We did find significant differences in yield with Silo 700 BMR having the highest yield with 31.62 tons/acre and GS125 having the lowest with 20.53 tons/acre. We also saw significant differences in crude protein with ExpGD having the highest (3.47%) and Silo 700 BMR (1.93%) being the lowest.
    • Effect of Planting Date on Wheat Yield in Yuma, 2013

      Ottman, M. J.; Ottman, Michael J.; School of Plant Sciences / Maricopa Ag Center, University of Arizona (College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2013-05)
      Planting dates are known to affect wheat yields. Previous research has shown that the optimum planting date in Yuma is December 15 to January 15. Wheat is sometimes sown later than this in the Yuma area, and earlier planting dates have not been tested. To test a wide range of planting dates, six varieties(Duraking, Havasu, Joaquin, Kronos, WB-Mead, and Yecora Rojo) were planted at two seeding rates (160 and 240 lbs/A) and six planting dates at the beginning of each month from November through April at the Yuma Valley Agricultural Center. Grain yield averaged 6517 (Nov 4), 6339 (Dec 6), 6096(Jan 4), 5712 (Feb 1), 4962(Mar 1), and 3590(Apr 5). The late-flowering varieties performed relatively better at the earlier planting dates. Seeding rates of 160 and 240 lbs/A had no measureable effect on yield overall.
    • Alfalfa Variety Performance at Tucson, 2009-2010

      Ottman, M. J.; Smith, S. E.; Ottman, Michael J. (College of Agriculture, University of Arizona (Tucson, AZ), 2012-06)
      New alfalfa varieties are constantly being introduced into the marketplace. The number of varieties available for low-elevation desert areas in Arizona in the non-dormant class is over50. New varieties are introduced each year and unbiased yield comparisons are helpful to the grower to base the decision of whether or not to sow a new variety. The study reported here is part of the on-going effort to evaluate alfalfa variety performance in Arizona. A summary of alfalfa variety trials conducted by the University of Arizona can be found online at http://ag.arizona.edu/pubs/crops/az1267.pdf.
    • Silage Corn Variety Trial in Central Arizona

      Loper, Shawna; Subramani, Jay; Ottman, Michael J.; University of Arizona of Arizona Cooperative Extension, Pinal County; Maricopa Ag Center, University of Arizona (College of Agriculture, University of Arizona (Tucson, AZ), 2012-06)
      Ten varieties of silage corn were tested at the Maricopa Agricultural Center in Central Arizona. Information on silage corn yield and quality can help the dairy industry and silage growers choose varieties that best fit their needs. There were no significant differences between any of the varieties tested with respect to ‘yield per acre’, ‘crude protein’, NDF or ‘ash content'. We were able to find significant differences with ADF.
    • Invinsa Application to Reduce Water Stress Effects on Corn Growth and Yield at Maricopa, AZ, 2012

      Ottman, M. J.; Kimball, B. A.; Ottman, Michael J. (College of Agriculture, University of Arizona (Tucson, AZ), 2012-06)
      Invinsa blocks ethylene perception by plants and can reduce the negative effects of water stress on crop growth. The objective of this study is to measure the effect on corn growth and yield of Invinsa application at incipient water stress. A study was conducted at the University of Arizona Maricopa Agricultural Center where Invinsa was applied on 15 May in blocks with adequate or deficit irrigation. The deficit irrigation block received no irrigation water for 7 days past incipient stress beginning on 15 May, but otherwise received adequate water during the other parts of the season. Invinsa had little or no effect on crop growth measured at five different dates during the growing season. Invinsa had no effect on grain yield, grain moisture content, harvest index, ear number, kernels per ear, kernel weight, and silking date. We were not able to measure an effect of Invinsa on photosynthetic rate, conductance to water, intercellular CO2 concentration, vapor pressure deficit, or leaf temperature. However, Invinsa increased daily water use at various time periods, particularly in the adequate irrigation regime. The lack of a response this year to Invinsa, other than water use, is similar to the results from last year where no consistent response was measured. Invinsa has increased corn yield in other regions, and heat and/or water stress at the Maricopa may mask the effects of Invinsa or render it ineffective.
    • Determination of Optimal Planting Configuration of Low Input and Organic Barley and Wheat Production in Arizona, 2012

      Ottman, M. J.; Andrade-Sanchez, P.; Ottman, Michael J. (College of Agriculture, University of Arizona (Tucson, AZ), 2012-06)
      Markets for organic barley and wheat are expanding. A major problem growing organic barley and wheat is controlling the weeds. Organic barley and wheat were grown in conventional 6-inch drill spacing but also in 30 inch spacing so weeds could be cultivated in a study at the Larry Hart Farm near Maricopa. The weed pressure was moderate and the weed biomass was about 1 to 5% of the crop biomass near maturity. The primary weed was Palmer amaranth. Grain yields of the wheat (durum) were similar regardless of row spacing, but the barley grain yields were 3921 lbs/acre in the 6 inch spacing and 2530 lbs/acre in the 30 inch spacing.
    • Small Grains Variety Evaluation at Arizona City, Coolidge, Maricopa and Yuma, 2012

      Ottman, M. J.; Ottman, Michael J. (College of Agriculture, University of Arizona (Tucson, AZ), 2012-06)
      Small grain varieties are evaluated each year by University of Arizona personnel. The purpose of these tests is to characterize varieties in terms of yield and other attributes. Variety performance varies greatly from year to year and several site-years are necessary to adequately characterize the yield potential of a variety. A summary of small grain variety trials conducted by the University of Arizona can be found online at http://ag.arizona.edu/pubs/crops/az1265.pdf.
    • Alfalfa Variety Performance at Tucson, 2007-2008

      Ottman, M. J.; Smith, S. E.; Ottman, Michael J. (College of Agriculture, University of Arizona (Tucson, AZ), 2012-06)
      New alfalfa varieties are constantly being introduced into the marketplace. The number of varieties available for low-elevation desert areas in Arizona in the non-dormant class is aver50. New varieties are introduced each year and unbiased yield comparisons are helpful to the grower to base the decision of whether or not to sow a new variety. The study reported here is part of the ongoing effort to evaluate alfalfa variety performance in Arizona. A summary of alfalfa variety trials conducted by the University of Arizona can be found online at http://ag.arizona.edu/pubs/crops/az1267.pdf.
    • Effects of Zn fertilizer on cadmium accumulation in durum wheat

      Wang, Guangyao (Sam); Ottman, Michael; Chaney, Rufus L.; Ottman, Michael J.; School of Plant Sciences / Maricopa Ag Center, University of Arizona; School of Plant Sciences, University of Arizona; Environmental Management and Byproduct Utilization Laboratory, USDA-ARS (College of Agriculture, University of Arizona (Tucson, AZ), 2012-02)
      Proposed reduction in maximum allowable cadmium (Cd) level in wheat grain from 0.2 to 0.15 ppm by European Union (EU) could affect Arizona wheat growers substantially. The possible breeding programs and management practices needs to be developed to keep the industry competitive for this major market. In this study, we used two durum wheat cultivars (Ocotillo representing higher Cd genotypes and Havasu representing lower Cd genotypes) to study the potential of Zn fertilizer (as ZnSO₄ and ground tire rubber) to reduce Cd uptake in durum wheat at Yuma Ag Center. While cadmium level in the two varieties were different significantly, applying ZnSO₄ or ground rubber did not affect grain cadmium level, grain yield, or protein content significantly.
    • Silage Corn Variety Trial in Central Arizona

      Subramami, Jay; Loper, Shawna; Ottman, Michael J.; Maricopa Ag Center, University of Arizona; University of Arizona Cooperative Extension, Pinal County (College of Agriculture, University of Arizona (Tucson, AZ), 2012-02)
      Information on silage corn yield and quality can help silage growers and users choose varieties that best fit their needs and area. We conducted a silage corn variety trial using seven varieties for use in Central Arizona. Variety 28Z47 produced the higher silage yield with an average of 30.4 ton/acre and the variety 28V71 had the highest crude protein content (8.13%) among the eight. Varieties that produced higher yield, higher crude protein, and lower NDF than the average of the eight varieties were 851VT3 and TMF-2L-872.
    • Response of Wheat and Barley Varieties to Phosphorus Fertilizer, 2011

      Ottman, M. J.; Ottman, Michael J. (College of Agriculture, University of Arizona (Tucson, AZ), 2012-02)
      Phosphorus fertilizer represents a significant portion of the cost of producing small grains. Some evidence exists that there are differences in the ability of small grain varieties to take phosphorus up from the soil and utilize this nutrient in the grain. The objective of this study is to determine if barley and wheat varieties grown in Arizona differ in their response to phosphorus fertilizer. A study was conducted for the third year at the Maricopa Agricultural Center testing the response of 7 barley and 14 wheat (12 durum wheat and 2 bread wheat) varieties to 2 phosphorus rates (0 and 100 lbs P₂O₅/acre). Averaged over varieties, the grain yield increase due to phosphorus application of 100 lbs P₂O₅/acre was 346 lbs/acre for barley and 516 lbs/acre for wheat, similar to previous years. Despite the wide range of apparent yield response (0 to over 1000 lbs/acre) of the varieties to P fertilizer, these differences were not statistically significant. Furthermore, there was no consistency in the yield response of the varieties between this year and last year. Some of the varieties that responded greatest to P fertilizer last year, responded least this year, and vice versa. Therefore, there appears to be no differences in the response of barley and wheat varieties typically grown in Arizona to phosphorus fertilizer.
    • Late N management in durum wheat using crop models and canopy reflectance

      Wang, Guangyao (Sam); Ottman, Michael; Thorp, Kelly; Ottman, Michael J.; School of Plant Sciences / Maricopa Ag Center, University of Arizona; School of Plant Sciences, University of Arizona; Arid-Land Ag Research Center, USDA-ARS, Maricopa, AZ (College of Agriculture, University of Arizona (Tucson, AZ), 2012-02)
      Optimizing late N applications in durum wheat is highly needed to obtain adequate protein levels without affecting grain yield. A simple and rapid method for estimating crop yield at flowering stage and crop N status is required to make immediate N application decisions for increasing grain protein content. There were significant differences in grain yield and grain protein among N treatments and durum varieties. Using information on soil properties, weather data, crop management, and variety growth, DSSAT crop model predicted durum grain yield accurately. Canopy reflectance index NDVI at flowering time were closely correlated with crop yield and protein content. The results indicate the potential of using crop models and canopy reflectance index in durum wheat yield prediction and N management.
    • Invinsa Application to Reduce Water Stress Effects on Corn Growth and Yield at Maricopa, AZ, 2011

      Ottman, M. J.; Kimball, B. A.; Ottman, Michael J. (College of Agriculture, University of Arizona (Tucson, AZ), 2012-02)
      Invinsa blocks ethylene perception by plants and can reduce the negative effects of water stress on crop growth. The objective of this study is to measure the effect on corn growth and yield of Invinsa application at incipient water stress. A study was conducted at the University of Arizona Maricopa Agricultural Center where Invinsa was applied on 15 June and 20 June in blocks with adequate irrigation or deficit irrigation, which received no irrigation water for 10 days past incipient stress beginning on 15 June. Invinsa had inconsistent effects on corn growth and yield. The most notable effect of Invinsa, however, was an increase in total plant yield from 11.09 to13.43 t/a measured on 23 July and from 11.36 to 13.61 t/a measured on 13 Aug in the adequate irrigation block for Invinsa application on 15 June. However, Invinsa had no effect on final grain yield. The lack of a consistent response to Invinsa may be explained by the higher than optimum temperature at time of application or other unknown factors.
    • Small Grains Variety Evaluation at Arizona City, Coolidge, Maricopa and Yuma, 2011

      Ottman, M. J.; Ottman, Michael J. (College of Agriculture, University of Arizona (Tucson, AZ), 2012-02)
      Small grain varieties are evaluated each year by University of Arizona personnel. The purpose of these tests is to characterize varieties in terms of yield and other attributes. Variety performance varies greatly from year to year and several site-years are necessary to adequately characterize the yield potential of a variety. A summary of small grain variety trials conducted by the University of Arizona can be found online at http://ag.arizona.edu/pubs/crops/az1265.pdf.
    • Determination of optimal planting configuration of low input and organic barley and wheat production in Arizona

      Ottman, M. J.; Andrade-Sanchez, P.; Ottman, Michael J. (College of Agriculture, University of Arizona (Tucson, AZ), 2012-02)
      Markets for organic barley and wheat are expanding. A major problem growing organic barley and wheat is controlling the weeds. Organic barley and wheat were grown in conventional 6-inch drill spacing but also in 30 inch spacing so weeds could be cultivated in a study at the Larry Hart Farm near Maricopa. The weed pressure was moderate and the weed biomass was about 16 to 26% of the crop biomass near maturity. The primary weed was canarygrass and the secondary weed was malva. Grain yields of the wheat (durum) were similar regardless of row spacing, but the barley grain yields were 4327 lbs/acre in the 6 inch spacing and 3330 lbs/acre in the 30 inch spacing.
    • Nitrogen Fertilizer Requirement of Feed and Malting Barley Compared to Wheat, 2011

      Ottman, M. J.; Ottman, Michael J. (College of Agriculture, University of Arizona (Tucson, AZ), 2012-02)
      Barley is generally thought to require less nitrogen fertilizer than wheat, but how much less has not been clearly documented. The purpose of this study is to compare the nitrogen fertilizer requirements of barley and wheat. A study was conducted at the Maricopa Agricultural Center testing the response of 2 durum wheats (Kronos and Havasu), 2 bread wheats (Yecora Rojo and Joaquin), 2 feed barleys (Baretta and Nebula), and 2 malting barleys (Conrad and Moravian 69) to 7 rates of nitrogen fertilizer (0, 30, 60, 90, 120, 150, and 180 lbs N/acre). The surface soil was relatively high in nitrate at planting (19 ppm NO₃-N) contributing an estimated 76 lbs N/acre. Maximum yield was obtained at 156 (durum), 147 (wheat), 137 (feed barley), and 127 (malting barley) lbs N/acre. However, since the yield of durum and bread wheat was higher than feed and malting barley, the nitrogen fertilizer per 100 pounds of grain yield was similar for these crop types (~2.37 lbs N per 100 lbs of grain). If the 76 lbs N/a of nitrogen estimated to be available from the surface soil were included, then about 3.62 lbs of N would have been required per 100 lbs of grain for both wheat and barley. The N requirement reported in this study does not include the extra N potentially needed for wheat to obtain acceptable protein levels. In conclusion, wheat required more nitrogen fertilizer than barley to obtain maximum yield in our study, but the amount of nitrogen fertilizer required per 100 pounds of grain was similar.
    • Small Grains Variety Evaluation at Maricopa, Coolidge and Yuma, 2010

      Ottman, M. J.; Ottman, Michael J. (College of Agriculture, University of Arizona (Tucson, AZ), 2010-09)
      Small grain varieties are evaluated each year by University of Arizona personnel. The purpose of these tests is to characterize varieties in terms of yield and other attributes. Variety performance varies greatly from year to year and several site-years are necessary to adequately characterize the yield potential of a variety. A summary of small grain variety trials conducted by the University of Arizona can be found online at http://ag.arizona.edu/pubs/crops/az1265.pdf.
    • Suboptimal Irrigation Strategies for Alfalfa in the Lower Colorado Region, 2009

      Ottman, Michael J.; Ottman, Michael J. (College of Agriculture, University of Arizona (Tucson, AZ), 2010-09)
      Alfalfa has the highest water requirement of any crop grown in Arizona, and any strategies that conserve water growing this crop could have a large impact on water availability in the state. The purpose of this study is to determine yield and profitability of sub-optimal irrigation strategies in alfalfa. An irrigation study was conducted at the University of Arizona Maricopa Agricultural Center on a sandy clay loam soil. The following irrigation treatments are included in this study: 1) One irrigation per cutting, 2) Two irrigations per cutting, 3) Summer (August) irrigation termination, 4) Winter (December, January, February) irrigation termination, and 5) Summer and Winter irrigation termination. The Winter irrigation termination treatments were initiated in December 2009 and data is not available yet for these treatments. The amount of water applied from January through November 2009 was 69.7 inches (one irrigation per cut), 80.5 inches (two irrigations per cut), and 78.6 (Summer irrigation termination). The annual hay yields were 12.5 tons/acre (one irrigation per cut), 13.7 tons/acre (two irrigations per cut), and 12.9 tons/acre (Summer irrigation termination). Sub-optimal irrigation increased the forage quality by decreasing fiber (ADF and NDF) and increasing protein content. Sub-optimal irrigation did not reduce stand density. The water use efficiency of applied water (plus rainfall) was not affected by irrigation treatment.