• Salt Tolerance and Cation Interaction in Alkali Sacaton at Germination

      Hyder, S. Z.; Yasmin, S. (Society for Range Management, 1972-09-01)
      Salt tolerance and cation interaction in alkali sacaton (Sporobolus airoides Torr.) was studied during the germination stage. Germination was inhibited at a concentration of 275 meq/liter of sodium chloride. Mannitol and other salts at iso-osmotic pressure restricted germination in the following decreasing order: MgCl2, KCl, CaCl2, NaCl, and mannitol. Inhibitory effects of magnesium on germination were partially counteracted by calcium and sodium. Greater recovery in germination was noted by addition of calcium than sodium in seeds previously treated with a high concentration of magnesium chloride. The role of sodium and calcium in counteracting magnesium effects has been discussed. It is also concluded that specific effects of salts are more important than osmotic effects on the seed germination of this species.
    • Some Factors Influencing Tolerance to Moisture Stress of Three Range Grasses

      Schlatterer, E. F.; Hironaka, M. (Society for Range Management, 1972-09-01)
      Pre-conditioning of bluebunch wheatgrass, squirreltail and Thurber stipa plants by exposure to different temperatures and watering schedules affected their tolerance to moisture stress. Plants conditioned under high or low temperatures were more resistant to moisture stress than plants conditioned at moderate temperature. Plants grown in fertile mound soil were less conditioned to withstand moisture stress than those grown in less fertile intermound soil.
    • Three Methods of Determining Diet, Utilization, and Trampling Damage on Sheep Ranges

      Laycock, W. A.; Buchanan, H.; Krueger, W. C. (Society for Range Management, 1972-09-01)
      Esophageal fistula sampling and ocular utilization estimates gave similar figures for dietary composition and for percentage utilization by sheep for most plant species in the tall-forb type. The paired-plot method gave higher utilization figures than the above methods because it estimated not only herbage eaten, but also that trampled. As a result, this method overestimated the dietary composition of species most susceptible to trampling damage; trampling accounted for one-half to two-thirds of the herbage removed by grazing.
    • Vegetation Changes as a Result of Soil Ripping on the Rio Puerco in New Mexico

      Aldon, A. F.; Garcia, G. (Society for Range Management, 1972-09-01)
      Soil ripping in 1963 effectively reduced runoff on the San Luis watershed of the Rio Puerco, New Mexico, and caused a favorable shift in forage production from galleta to alkali sacaton. Ripping effects on runoff are short-lived, but forage production patterns may persist for 10 years.
    • Western Coneflower—A Noxious Species?

      Florez, A.; McDonough, W. T.; Balls, L. D. (Society for Range Management, 1972-09-01)
      In laboratory tests, dilute foliar extracts of western coneflower (Rudbeckia occidentalis Nutt.) inhibit germination and seedling growth of seeded grasses as do those of some supposedly innocuous species. Under natural conditions on aspen range, measurements of plants of mountain brome growing in close association with coneflower gave doubtful evidence of suppressed growth. Large doses of dried aerial parts of coneflower force-fed to sheep produced no evidence of toxicity or other distress. We found no evidence of coneflower posing any special threat on mountain range, except as a relatively unpalatable increaser species.