• Comparison of the Reference Unit Method and Dimensional Analysis Methods for Two Large Shrubby Species in the Caatinga Woodlands

      Kirmse, R. D.; Norton, B. E. (Society for Range Management, 1985-09-01)
      The reference unit technique was compared with the dimensional analysis approach for estimating large shrub foliage biomass in Northeast Brazil. The techniques were tested on coppicing jurema (Mimosa acutistipula Benth.) and pau branco (Auxemma oncocalyx [Fr. Alem.] Taub.). Both methods provided good estimates of foliage weight. The coefficients of determination for the reference unit approach ranged from .890 to .985. The r2 values obtained in applying the dimensional analysis method were .937 and .948. Improvements in estimates with the reference unit method were obtained when (1) a branch unit of 19% of total plant foliage was used versus a unit of only 7%, (2) the branch unit resembled the appearance of the branching of the plant being estimated, and (3) estimations of 3 judges were averaged.
    • Cattle Diets on Shortgrass Ranges with Different Amounts of Fourwing Saltbush

      Shoop, M. C.; Clark, R. C.; Laycock, W. A.; Hansen, R. M. (Society for Range Management, 1985-09-01)
      Inadequate data have existed concerning cattle preferences for fourwing saltbush [Atriplex canescens (Pursh) Nutt.] on ranges where it is dominant, and concerning composition of cattle diets on the central shortgrass plains. In this study, food habits of cattle were estimated from fecal analyses on winter and summer pastures containing either abundant or sparse fourwing saltbush (saltbush). The abundant saltbush was on overflow and/or sandy plains range sites; sparse saltbush was on loamy plains range sites. Saltbush was a major constituent of cattle diets where abundant. The proportion of saltbush in winter diets peaked during March (55%) and declined during April. Saltbush was absent from summer diets during July, peaked during August (42%), and declined abruptly during September. Where abundant, saltbush was also the primary constituent of the forb-shrub component of diets during both winter (mean=72%) and summer (mean=44%). Deleting saltbush from the data, cattle foods consumed on pastures with sparse and abundant saltbush were correlated (0.84) during summer, but were not correlated (0.25) during winter. Relative to species frequencies in pastures, cattle diets on loamy plains range sites (sparse saltbush) contained notably larger portions of sedges (Carex spp. L.), goosefoots (Chenopodium spp. L.), and fringed sagewort (Artemisia frigida Willd.), during winter and goosefoots and scarlet globemallow [Sphaeralcea coccinea (Nutt.) Rydb.] during summer, than diets on sandy plains and overflow sites (abundant saltbush). Saltbush is a preferred and valuable forage for cattle on the central shortgrass plains, and it should be managed to maintain or improves its productivity.
    • Cattle Diets in a Ponderosa Pine Forest in the Northern Black Hills

      Uresk, D. W.; Paintner, W. W. (Society for Range Management, 1985-09-01)
      A cattle diet study was conducted in the northern Black Hills of South Dakota and Wyoming. Forty-eight plants were identified in cattle fecal material. Grasses in the feces averaged 54%, forbs 17%, and shrubs-trees 28% over the grazing season. Sedges (Carex spp.) and wheatgrass (Agropyron spp.) were the most abundant plants found in the feces throughout the season. Bur oak (Quercus macrocarpa), ponderosa pine (Pinus ponderosa), and Oregon grape (Berberis repens) were common in the diet. Shrubs and trees made up 37% of the diet in September. Similarities and rank order correlations of diets with available forage were low in August, indicating that cattle were selectively grazing.
    • Browse Quality Response to Forest Fertilization and Soils in Florida

      Wood, J. M.; Tanner, G. W. (Society for Range Management, 1985-09-01)
      Spring leaves of red maple (Acer rubrum) and inkberry (Ilex glabra) from slash pine (Pinus elliottii) plantations fertilized with diammonium phosphate 4 to 9 years prior to collection were higher in phosphorus (P) than leaves from an unfertilized plantation. The nitrogen (N) content of inkberry leaves also was higher in spring. During the summer, in vitro organic matter digestibility (IVOMD) was higher in both species and P was higher in inkberry on fertilized plantations. However, any residual effect of fertilization on nutrient concentrations was overshadowed by a decrease in P and N and an increase in calcium (Ca) in the summer. The effect of soil series on nutrient values was negligible, with the exception of Ca, which was higher on a somewhat poorly drained Dunbar soil series than on a poorly drained Bladen soil series. Nutritive value of both browse plants was limited by low IVOMD and P concentrations, which never attained maintenance levels required by white-tailed deer (Odocoileus virginianus).
    • An Energy Model for Adult Female Caribou of the Denali Herd, Alaska

      Boertje, R. D. (Society for Range Management, 1985-09-01)
      Estimates of the energy costs of resting, activity, and productive processes from the literature were applied to caribou activity budgets and movements documented during 1978-80 to estimate seasonal and annual energy requirements of adult female caribou (Rangifer tarandus granti) in Denali National Park and Preserve. Energy requirements were 45% lower in winter than summer, primarily because of a 21% reduction in resting metabolic rate and benefits of fat catabolism in winter, and high summer costs of lactation, fat deposition, and activity. Estimated energy requirements totaled 38.2 MJ day-1 during the insect season, 36.7 during summer migration, 34.2 during fall migration, 31.9 during prerut and rut, 29.3 during calving and postcalving, 23.7 during early and late winter migrations, 21.6 during early winter, 20.9 during late winter, and 20.5 during midwinter. Annual energy requirements, including costs of pregnancy (368.6 MJ) and lactation (560.3), totaled 9,870 MJ, excluding costs of cratering through snow and apparently minor costs of physiological stress. Compared to studies of food energy requirements of penned caribou, the model gives accurate predictions of total metabolizable energy requirements when allowances are made for the relative inactivity of penned animals.