• Evaluation of Nitrogen Fertilization Practices for Surface-Irrigated Lemon Trees - 2012

      Wright, Glenn C; Department of Plant Sciences, University of Arizona; Yuma Agriculture Center, Yuma, AZ (College of Agriculture, University of Arizona (Tucson, AZ), 2015-02)
      Lisbon lemons were treated with N levels ranging from 0.5 to 3.0 lbs. N per tree annually. Fourth–season yield results from the trial show significant effects of the treatments upon overall yield and leaf N concentrations, but no effect upon fruit packout. Treatments did lead to a significant effect upon leaf nutrient concentration. Total cumulative yields from 2008 to 2012 (not including the freeze-affected 2011-12 season) were significantly affected by the treatments. Trees treated annually with 2.0 lbs N had the greatest yield, which represented a 12% increase over the yield of trees treated with just 0.5 lbs. N annually.
    • Sudangrass Hay Production in the Irrigated Deserts of Arizona and California

      Knowles, Tim C.; Ottman, Michael J. (College of Agriculture, University of Arizona (Tucson, AZ), 2015-05)
      Foreign sudangrass hay buyers want dust-free hay with a bleached light green color and a stem diameter less than one quarter of an inch. Two types of sudangrass hybrids are currently grown in the United States: true sudangrass hybrids and sorghum-sudan hybrids. Sudangrass and related hybrids are annual warm season grasses grown for pasture, green chop, silage, and hay. Sudangrass produces well on all soil types, however best yields are obtained on well-drained, deep loam soils that have a high capacity to absorb and hold water. Sufficient nitrogen should be applied at planting to ensure establishment of the crop and hasten development. Typically, 40 to 80 pounds of actual nitrogen per acre are suggested at planting, based on results from a preplant nitrate-nitrogen soil test. This should be followed by split applications of 60 to 120 pounds actual nitrogen per acre in irrigation water following each cutting. Harvest sudangrass when it is at least 18 to 24 inches tall at the first cutting. Nitrates present in hay crops are considered toxic to many classes of livestock. Most cases of hydrocyanic or prussic acid poisoning are caused by the ingestion of plants that contain cyanogenetic glucosides. Cyanogenetic glucoside itself is non-toxic but hydrocyanic acid.