• Phytotoxic Effects of Bunchgrass Residues on Germination and Initial Root Growth of Yellow Sweetclover

      Rietveld, W. J. (Society for Range Management, 1977-01-01)
      The subclimax bunchgrasses Arizona fescue and mountain muhly promptly invade disturbances in the climax ponderosa pine forest and develop into dense, persistent, impenetrable communities. Yellow sweetclover and several weed species invade disturbances in the bunchgrass community, flourish briefly, then decline as the bunchgrasses recover the site. Extracts prepared from green foliage and straw of fescue and muhly significantly reduced sweetclover seed germination and retarded speed of elongation and mean radicle length. Leachates from live grass foliage significantly inhibited sweetclover seed germination, suggesting that leaching may be a route of release of the inhibitor.
    • Plains Pricklypear Is a Good Forage for Cattle

      Shoop, M. C.; Alford, E. J.; Mayland, H. F. (Society for Range Management, 1977-01-01)
      Singed plains pricklypear was assessed as a cattle forage. In an 84-day feeding trial, six pairs of heifers were individually fed a basal ration of hay and cottonseed meal at 2.3% of initial bodyweight. One heifer in each pair also ate singed pricklypear offered ad libitum. Pricklypear increased total dry matter consumption 43% and weight gain 72%. The heifers experienced no digestive problems during the trial or ensuing 60 days on pricklypear range. Chemical analyses and microdigestion trials indicated that digestibility of pricklypear was equal or superior to that of high quality alfalfa hay. Pricklypear contained about 40% more soluble carbohydrates than alfalfa hay, but contained only 3.4% digestible protein. Therefore, rations containing pricklypear would usually require protein supplementation. We concluded that singed pricklypear was a palatable and nutritious feed and should be evaluated as an additional forage on shortgrass range.
    • Plant Succession Following Chaining of Pinyon-Juniper Woodlands in Eastern Nevada

      Tausch, R. J.; Tueller, P. T. (Society for Range Management, 1977-01-01)
      This study was undertaken to determine some of the long-term effects of secondary succession on tree control in pinyon-juniper woodlands by cabling and chaining with "debris in place," a technique used for about two decades. Plant species representative of all the successional stages we observed following treatment exist simultaneously from treatment. These observed changes were primarily changes in relative abundance resulting from differences in the growth rates and competitive abilities of the species concerned. Competitive ability appears directly related to the length of time following treatment that a species is able to maintain an increased growth rate. The trees maintain this increased growth for two to three times as long as any understory species studied. The result is a steady reduction of understory cover and production beyond the fifth to eight year following treatment, depending on site.
    • Reseda lutea: A Multipurpose Plant for Arid and Semiarid Lands

      Moghaddam, M. R. (Society for Range Management, 1977-01-01)
      Reseda lutea is a plant well adapted to the arid and semiarid rangelands of Iran. It provides early spring green growth, is palatable to sheep and goats, and compares favorably with alfalfa in nutritive content.
    • Seasonal Use of Soil Water by Mature Velvet Mesquite

      Cable, D. R. (Society for Range Management, 1977-01-01)
      Mesquites used water consistently to a depth of 3 m and outward to 10 m beyond the crowns, but use at 15 m was limited mainly to drier periods when water supplies closer to the trees were depleted. With the start of spring growth, water was extracted most rapidly from the surface layers. As the season advanced, the watersupply zone became increasingly thicker. Rates of extraction were highest immediately after recharge in early spring and early summer, and lowest in late fall. Differences in available water in the soil accounted for 72 to 88% of the variation in rates of extraction. The competitive effect of velvet mesquite on perennial grasses is most severe in the upper 37.5 cm of soil under and near the mesquite crowns, and gradually decreases with distance into adjacent openings. The competitive effect in the openings is much more severe in dry years than in wet years.
    • Species Susceptibility to Atrazine Herbicide on Shortgrass Range

      Houston, W. R. (Society for Range Management, 1977-01-01)
      Atrazine was applied at 2 kg/ha for three consecutive years on shortgrass range in northeastern Colorado. The atrazine controlled all annual plant species, greatly reduced frequency of occurrence of cool-season perennial grasses, and increased drought survival of warm-season perennial grasses and two warm-season perennial forbs. Other species varied in their susceptibility to atrazine. The species frequency method of vegetation sampling used in this study provided reliable data for 27 of the approximately 100 species encountered on this range.
    • Squirreltail Seed Germination

      Young, J. A.; Evans, R. A. (Society for Range Management, 1977-01-01)
      Germination tests on squirreltail seed showed that three temperature regimes always produced optimum germination of 76 to 100%. We defined optimum as not statistically (p = 0.01) different from maximum. The always optimum temperature regimes were: (1) a constant 15 degrees C, (2) alternating 10/15 degrees C (16 hours cold/8 hours warm each day), and (3) 10/20 degrees C. When seed was produced in a year with good growing conditions, optimum germination extended over a wide range of temperatures. At optimum temperatures, the rate of germination was very rapid with a high percentage of total germination occurring within a week. The lack of inherent germination requirements that restrict germination, high germinability, and a rapid rate of germination help to explain the colonizing ability of this species.