• Effect of Onion Bed Shape on Accumulation of Soluble Salts and Sodium

      Knowles, Tim C.; Poole, Charles; Byrne, David N.; Baciewicz, Patti (College of Agriculture, University of Arizona (Tucson, AZ), 1999-10)
      An experiment was conducted to examine the effectiveness of knifing a vshaped notch into the center of raised onion beds for reducing soluble salt accumulation in the seed rows. Sodium salts accumulated within an 18 inch wide band in the top six inches of the knifed raised bed profile. Sodium salts accumulated primarily within a narrow six inch wide band, and to a somewhat lesser extent, within an 18 inch wide band in the top six inches of the conventional raised bed profile. Total soluble salts accumulated primarily within a six inch wide band in the top six inches of the knifed and conventional onion raised bed profiles.
    • Evaluation of Preemergence Herbicides for Early Season Onion Weed Control

      Knowles, Tim C.; Poole, Charles; Byrne, David N.; Baciewicz, Patti (College of Agriculture, University of Arizona (Tucson, AZ), 1999-10)
      Two experiments were conducted to determine the efficacy and safety of soil applied broadcast preemergent herbicides including Nortron, Prowl, Prefar, and Prefar + Prowl combinations applied at planting to fall seeded dry bulb onions. Crop stand reductions ranging from 10 to 33 percent resulted from Prowl 3.3EC use rates of 1.2 and 2.4 pt/acre. Prowl 3.3EC applied at 0.6 pt/acre, Prefar 4E applied at 4 and 6 qt/acre, Nortron 4SC applied at 2 pt/acre, and the combination of 0.6 pt Prowl 3.3 EC plus Prefar 4E were safe on fall seeded onions. Prefar plus Prowl combinations also provided winter weed control equal to or better than the standard 14 lb/acre Dacthal 75WP.