• Alfalfa Irrigation Termination, Maricopa

      Ottman, M. J.; Roth, R. L.; Ottman, Michael (College of Agriculture, University of Arizona (Tucson, AZ), 1994-12)
      Alfalfa irrigation is often withheld as a water conservation measure in Arizona. The objective of this research was to test the hypothesis that alfalfa can be permanently damaged by withholding irrigation water. Irrigation was terminated during the summer (July or August through September) or summer through winter (July or August through mid -March) on a Casa Grande sandy loam at Maricopa. Irrigation termination at Maricopa was not detrimental to stand although hay yields were depressed from 1.47 to 1.28 tons per acre following the second cycle of summer irrigation termination and from 1.57 to 1.23 tons per acre per cutting following summer through winter irrigation termination. Alfalfa water use was reduced by irrigation termination even after irrigation was resumed. Total nonstructural carbohydrates in the roots were never less than the control during irrigation termination but decreased relative to normally irrigated alfalfa when irrigation resumed.
    • Alfalfa Irrigation Termination, Yuma

      Ottman, M. J.; Tickes, B. R.; Ottman, Michael (College of Agriculture, University of Arizona (Tucson, AZ), 1994-12)
      Alfalfa irrigation is often withheld as a water conservation measure in Arizona. The objective of this research was to test the hypothesis that alfalfa yield and stand can be permanently damaged by withholding irrigation water. Irrigation was terminated during the summer (July through October) or winter (November through February) on a Superstition sand in Yuma. Summer irrigation termination reduced plant density from 4 to 1.5 plants per square foot and reduced hay yield from 0.76 to 0.27 tons per acre per cutting after irrigation was resumed. Winter irrigation termination had no residual effect on yield or plant density. Termination of alfalfa irrigation can permanently damage stands and reduce yield on sandy soil.
    • Alfalfa Variety Trial in Southeastern Arizona, 1992-1993

      Clark, L. J.; Carpenter, E. W.; Cluff, R. E.; Ottman, Michael (College of Agriculture, University of Arizona (Tucson, AZ), 1994-12)
      Twenty alfalfa varieties with Fall Dormancy ratings of 8 or 9 were tested in a replicated small plot trial on the Safford Agricultural Center. The leading variety after two years of cuttings is Mesa (formerly known as 84D92, an experimental from MBS, Inc). Two other varieties with FD ratings of 6 and 10 were included in the study for comparison. Heat units with thresholds of 77° F and 40° F are included for each cutting in the study.