• Subterranean Clover on Southern Pine Range: Potential Benefits to Game

      Ribbeck, K. F.; Johnson, M. K.; Dancak, K. (Society for Range Management, 1987-03-01)
      Wildlife habitat is an important component of forested lands in the South. We examined effects of silvicultural practices and understory management on abundance of arthropods for wild turkey (Meleagris gallopavo) and bobwhite (Colinus virginianus). Plots (roughtly equal to 0.1 ha) of southern pine timber (25-35 years old) were thinned or cleared and were planted with subterranean clover (Trifolium subterraneum) or were allowed to produce native vegetation. Arthropods were most abundant in clearings for both understory treatments: 127 +/- 15 (subterranean clover), 45 +/- 5 (native) per plot. Abundance of arthropods on pine forested plots with a subterranean clover understory was often greater than abundance of arthropods on cleared plots with native vegetation. Many of the arthropods sampled were the kinds often used by wild turkey and bobwhite. Subterranean clover production on forested plots was about 70% of production on cleared plots. Arthropods from 5 of 8 orders were significantly (P<0.05) more abundant in subterranean clover plots compared to native vegetation. Abundance of arthropods was significantly (P<0.05) associated with forage yield. Dead subterranean clover provided more arthropods in summer than live native vegetation. Planting subterranean clover in Southern pine timber offers a good alternative to removal of timber production for improving wildlife habitat and for integrating livestock and game management practices. Costs for establishing (roughly equal to $100/ha) and maintaining (roughly equal to $50/ha/yr) subterranean clover under pine timber are less than the potential loss in timber revenue ($125 to 340/ha/yr) associated with maintaining clearings.
    • Technical Notes: Survival Analysis of Single and Twin Lambs

      Scrivner, J. H.; Dally, M. R.; Howard, W. E. (Society for Range Management, 1987-03-01)
      We illustrate the use of life tables and survival analysis for evaluating data on livestock losses. The techniques are used to compare the rate of coyote (Canis latrans) predation on single and twin lambs. Based on the number of lambs known to have been killed by predators, the survivorship of single and twin lambs was not significantly different (P>0.05) for any year of the study. Survival functions which can be generated and used to evaluate data on livestock losses include the cumulative proportion of livestock surviving at the end of an interval, probability density, and hazard rate.
    • Temperature and Scarification Effects on Germination of Prostrate Bundleflower Seeds

      Fulbright, T. E.; Flenniken, K. S. (Society for Range Management, 1987-03-01)
      A hard seed coat restricts germination of prostrate bundleflower [Desmanthus virgatus var. depressus (Humbolt and Bonpland ex Willd.) Turner] seeds. Our objectives were to determine: (1) the effects of temperature on germination of scarified and untreated seeds in the light and dark and (2) the efficacy of various presowing treatments in increasing germination. Scarified (nicked with a razor blade) and untreated seeds were germinated at 5-15, 10-20, 15-25, 20-30, 25-35, and 30-40 degrees C (12 hours - 12 hours) in the dark or with light during the warmer temperature. Effects of scarification with 17 M H2 SO4, hot (80 degrees C) water, 0.7 mol liter-1 NaOCl, 2.9 mol liter-1 H2O2, and nicking with a razor blade on germination were compared. Maximum germination of untreated seeds was only 6%. Germination of scarified seeds exceeded 90% at 15-25 degrees C and higher temperatures. Light did not affect germination at optimal temperatures for germination. Nicking seeds with a razor blade, soaking 40 minutes in 17 M H2 SO4, and soaking 25 minutes in hot (80 degrees C) water resulted in 91, 88, and 78% germination, respectively, compared to 3% for controls. Our results indicated that, for best germination, seeds should be soaked 40 minutes in 17 M H2 SO4 or nicked with a razor and planted when mean minimum-maximum soil temperatures exceed 15-25 degrees C.
    • Understory Herbage Production of Major Soils within the Black Hills of South Dakota

      Bennett, D. L.; Lemme, G. D.; Evenson, P. D. (Society for Range Management, 1987-03-01)
      Two-year understory production was determined on 6 major forest soils across 2 geomorphic regions in the Black Hills of South Dakota. Stepwise multiple regression was used to determine those variables best explaining yield variability. Canopy cover, basal area, soils, May-June precipitation, and soil × cover interactions further improved the models, which accounted for 65 to 76% of the variability in herbage production. Footslope, nonskeletal soils had the highest herbage production (yielding 1,800 kg/ha at 0% canopy cover). The least developed, backslope, skeletal soil had the lowest herbage production (producing only 550 kg/ha at 0% canopy cover) from comparable areas of the Black Hills. Developed models can be used in conjunction with soil survey reports to estimate the forage potential of a given soil mapping unit. Results from this study emphasize the importance of considering the understory vegetation production potential of individual soil series when developing grazable woodland management plans. Soil-related production differences were most strongly expressed under conditions of limited overstory canopy cover.
    • Using Leaf Fluorescence for Evaluating Atrazine Tolerance of Three Perennial Warm-Season Grasses

      Bahler, C. C.; Moser, L. E.; Vogel, K. P. (Society for Range Management, 1987-03-01)
      Atrazine [6-chloro-N-ethyl-N′-(1-methylethyl)-1,3,5-triazine-2,4-diamine] blocks photosynthetic electron transport in susceptible plants. The energy from the interrupted electron transport is fluoresced from the leaves of atrazine-treated plants. The purpose of this study was to evaluate leaf fluorescence as a nondestructive bioassay of the relative atrazine tolerance of 3 perennial, warm-season grasses. Leaf section of switchgrass [Panicum virgatum L.] (high tolerance), indiangrass [Sorghastrum nutans (L.) Nash] (intermediate tolerance), and sideoats grama [Bouteloua curtipendula (Michx.) Torr.] (lower tolerance) were placed in distilled water for 20 min and then in atrazine solutions. Fluorescence readings were taken prior to and after the atrazine treatment with a portable fluorometer. The difference between the 2 readings provided a reliable measure with low variability of the relative atrazine tolerance of the grasses studied and was effective on greenhouse-and field-grown plants. Optimum atrazine concentrations and incubation periods were 10^-3 M (atrazine in distilled H2O and 30 min, respectively.
    • Variation in Utilization of Big Sagebrush Accessions by Wintering Sheep

      Welch, B. L.; McArthur, E. D.; Rodriguez, R. L. (Society for Range Management, 1987-03-01)
      We observed the effects of accessions of big sagebrush (Artemisia tridentata) on big sagebrush utilization by wintering domestic sheep. The sheep had continuous access to high quality alfalfa hay and were fed 0.28 kg of rolled barley per head per day. Utilization was expressed as a percent of the current year's vegetative growth consumed by the sheep and also as grams of dry matter eaten per stem. Utilization of accessions varied from 0 to 98% over 3 sites and from 0 to 7.112 g of dry matter per stem. The sheep tended to remove significant (60 to 70%) amounts of current growth from the more preferred accessions before removing even small (15%) amounts of less preferred accessions. If this is typical grazing behavior, preferred big sagebrush plants may be lost in areas subject to repeated grazing.
    • Variations in Physiological Metabolites and Chlorophyll in Sexual Phenotypes of 'Rincon' Fourwing Saltbush

      Tiedemann, A. R.; McArthur, E. D.; Freeman, D. C. (Society for Range Management, 1987-03-01)
      An experiment was conducted to determine if concentrations of chlorophyll and basic metabolites (total organic nitrogen (TN), total phosphorus (TP), and total nonstructural carbohydrates (TNC)) were an indication of the physiological vigor of the 3 sexual phenotypes of fourwing saltbush (Atriplex canescens (Pursh) Nutt.). Our basic hypothesis was that males, females, and plants capable of male and female sex expression (sexually labile) were equally vigorous as was manifested in chlorophyll and metabolite levels. In June, concentrations of chlorophyll a, b, and total chlorophyll in the male phenotype were greater than in either the female or the labile phenotypes. There were no differences among phenotypes for the other dates. Male plants had the highest levels of metabolites (TN, TP, and TNC) when any differences among sexual phenotypes were significant. There were basically no differences in metabolite concentration between the female and labile sexual phenotypes. Results indicate that part of the hypothesis should be rejected-that male, female, and sexually labile plants are equally vigorous based on concentrations of chlorophyll and metabolites. Part of the hypothesis, however, can be accepted-that females and labile plants are comparable in physiological vigor. Levels of all 3 metabolites showed striking trends among sample dates, which indicated that fourwing saltbush has the capability of rebuilding its levels of metabolites in the spring at the physiologically costly time of flowering. This may be related to the photosynthetic efficiency associated with its C-4 photosynthetic pathway.