• Non-Native Invasive Plants of Arizona

      Howery, Larry D.; Northam, Ed; Meyer, Walt; Arnold, Jennifer; Carrillo, Emilio; Egen, Kristen; Hershdorfer, Mary (College of Agriculture, University of Arizona (Tucson, AZ), 2016-12)
      The noxious weed problem in the western United States has been described as, a biological forest fire racing beyond control because no one wants to be fire boss. Indeed, when small weed infestations are left unchecked, they can grow exponentially and spread across the land much like a slow-moving biological wildfire. However, land consumed by fire usually recovers and is often more productive than before the fire occurred. On the other hand, land consumed by noxious weeds may be irreversibly changed and never again reach its full biological potential. Reviewed 12/2016, First Edition Published 2001
    • Non-Native Invasive Plants of Arizona

      Howery, Larry D.; Northam, Ed; Meyer, Walt; Arnold, Jennifer; Carrillo, Emilio; Egen, Kristen; Hershdorfer, Mary; Natural Resources & the Environment, School of (College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2009)
      The noxious weed problem in the western United States has been described as, a biological forest fire racing beyond control because no one wants to be fire boss. Indeed, when small weed infestations are left unchecked, they can grow exponentially and spread across the land much like a slow-moving biological wildfire. However, land consumed by fire usually recovers and is often more productive than before the fire occurred. On the other hand, land consumed by noxious weeds may be irreversibly changed and never again reach its full biological potential.
    • Principles of Obtaining and Interpreting Utilization Data on Rangelands

      Ruyle, George B.; Smith, Lamar; Maynard, Jim; Barker, Steve; Stewart, Dave; Meyer, Walt; Couloudon, Bill; Williams, Stephen; Univ Arizona, Coll Agr & Life Sci (College of Agriculture, University of Arizona (Tucson, AZ), 2016-10)
      A primary expression of stocking levels on rangeland vegetation is utilization defined as the proportion or degree of current years forage production that is consumed or destroyed by animals (including insects). Utilization may refer either to a single plant species, a group of species, or the vegetation as a whole. Utilization is an important factor in influencing changes in the soil, water, animal, and vegetation resources. The impact of a specific intensity of use on a plant species is highly variable depending on past and present use, period of use, duration of use, inter-specific competition, weather, availability of soil moisture for regrowth, and how these factors interact. Utilization data can be used as a guideline for moving livestock within an allotment with due consideration to season, weather conditions and the availability of forage and water in pastures scheduled for use during the same grazing season. In combination with actual use and climatic data, utilization measurements on key areas and utilization pattern mapping are useful for estimating proper stocking levels under current management. Utilization studies are helpful in identifying key and problem areas, and in identifying range improvements needed to improve livestock distribution. Reviewed 10/2016. Originally published 5/2007.
    • Principles of Obtaining and Interpreting Utilization Data on Rangelands

      Ruyle, George B.; Smith, Lamar; Maynard, Jim; Barker, Steve; Stewart, Dave; Meyer, Walt; Couloudon, Bill; Williams, Stephen; Natural Resources & the Environment, School of (College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2007-05)
      A primary expression of stocking levels on rangeland vegetation is utilization defined as the proportion or degree of current years forage production that is consumed or destroyed by animals (including insects). Utilization may refer either to a single plant species, a group of species, or the vegetation as a whole. Utilization is an important factor in influencing changes in the soil, water, animal, and vegetation resources. The impact of a specific intensity of use on a plant species is highly variable depending on past and present use, period of use, duration of use, inter-specific competition, weather, availability of soil moisture for regrowth, and how these factors interact. Utilization data can be used as a guideline for moving livestock within an allotment with due consideration to season, weather conditions and the availability of forage and water in pastures scheduled for use during the same grazing season. In combination with actual use and climatic data, utilization measurements on key areas and utilization pattern mapping are useful for estimating proper stocking levels under current management. Utilization studies are helpful in identifying key and problem areas, and in identifying range improvements needed to improve livestock distribution.