• Gypsum Application on Wheat at Coolidge, 1987

      Ottman, Mike; Stroehlein, Jack; Christian, Tom; Ottman, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1987-09)
      Gypsum is applied to alleviate the problems associated with sodium- affected soils, such as surface crusting and impeded water infiltration. Due to the uncertainties in identifying gypsum-responsive sites, field studies were initiated to further our understanding of conditions responsible for the response of wheat to gypsum applications. Gypsum was applied at rates ranging from 0 to 4 T/A on two commercial farms near Coolidge, AZ. No differences in wheat grain yield, grain protein, stand, grain bushel weight, or plant height were detected at the 5% probability level at either site with the exception of increased plant height at one site. The positive benefits of gypsum have been documented in the past with certain soils; this study is just one of many required to more positively define gypsum-responsive sites in Arizona. The economics of gypsum application involves delivery and application cost of gypsum and the change in yield and value of subsequent crops.
    • 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).