• A Comparison of Average Variable Costs of Private vs. Public Land Ranches in Southeastern Montana

      Lacey, J. R.; Workman, J. P. (Society for Range Management, 1986-07-01)
      A study was conducted in southeastern Montana to determine the effects of federal range grazing on cattle ranch average variable operating costs per animal unit. Data were obtained through personal interviews in 1980 with 68 ranches in six southeastern Montana counties. T-tests were used to determine if the average variable costs per animal unit were less on ranches that rely on federal ranges than on ranches that do not. Annual variable costs per animal unit averaged $158 and $144, respectively, for ranches obtaining 0-4% and 5-51% of total forage from federal lands. However, this difference was not statistically significant. Regression analysis did indicate that variable costs per animal unit were significantly affected by the percentage of total ranch income from crop sales.
    • A Hand-Portable Single Nozzle Rainfall Simulator Designed for Use on Steep Slopes

      Wilcox, B. P.; Wood, M. K.; Tromble, J. T.; Ward, T. J. (Society for Range Management, 1986-07-01)
      The objective of this study was to develop a small plot (1 m2) rainfall simulator operational on steep terrain in the Guadalupe Mountains of New Mexico. The simulator developed is hand-portable and consists of a spray head assembly mounted on 3 adjustable legs. A 946-liter tank equipped with a gasoline powered pump was connected to the spray head assembly via rubber garden hoses. On steep slopes gravity provided sufficient pressure to operate the simulator. Site selection was limited to areas where the water tank could be located in a suitable upslope position. The simulator has been used for 2 years on 170 plots and has proved durable. Advantages of this device are the low cost of construction and operation, and the flexibility in plot-site selection it provides. The principal disadvantages are associated with the single stationary nozzle, such as uneven application of water at small drop sizes and low kinetic energies.
    • An 18-Year Comparison of Control Methods for Wyoming Big Sagebrush in Southwestern Montana

      Wambolt, C. L.; Payne, G. F. (Society for Range Management, 1986-07-01)
      Four Wyoming big sagebrush (Artemisia tridentata ssp. wyomingensis Beetle and Young) control treatments: burning, spraying with 2,4-D, rotocutting, and plowing, along with no control (rest) were compared in southwestern Montana. Production data (excluding sagebrush) were collected 10 years and sagebrush canopy cover and understory basal cover were collected 8 years during the period 1963-1981. Sagebrush canopy was most effectively reduced by burning while plowing with seeding was least effective. Rest alone resulted in a 29% reduction in sagebrush canopy during the study period. By 1981, burning provided the most production from the dominant forage species (bluebunch wheatgrass (Agropyron spicatum (Pursh) Scribn.) and important vegetal classes, although burning and spraying were equally successful when production was totaled for all years sampled. Understory basal cover did not prove useful to evaluate treatment effectiveness.
    • Biomass Partitioning in 'Caucasian' and 'WW-Spar' Old World Bluestems

      Coyne, P. J.; Bradford, J. A. (Society for Range Management, 1986-07-01)
      Above- and belowground biomass dynamics of 'WW-Spar' (Bothriochloa ischaemum) and 'Caucasian' (B. caucasica) Old World bluestems were monitored under field conditions during spring-summer and summer-fall growing cycles in 1983. The objective was to document biomass partitioning patterns to complement earlier studies of leaf physiology and aboveground growth behavior in these 2 grasses. The standing crop of forage reached 500 and 694 g m-2 in WW-Spar and Caucasian, respectively, by the end of cycle 1 (11 July 1983). However, as in earlier studies, Caucasian was more sensitive to limited soil water so that its forage production and water-use efficiency showed a much greater decline in the second cycle than did these parameters in WW-Spar. At reproductive maturity, both grasses partitioned about 0.4 of total biomass to aboveground compartments (leaves, stems, stem bases, inflorescences) with Caucasian allocating more of its aboveground biomass to leaves and stems and WW-Spar more to stem bases. Excluding stem bases from the aboveground compartment showed that WW-Spar had the higher leaf/stem ratio. Root biomass declined significantly at the start of each growing cycle, but was similar in both grasses (peak root standing crop = 1,900 g m-2 to a depth of 1.2 m). Caucasian tended to partition slightly more of its root biomass to upper soil layers, WW-Spar more to lower layers. Across growing cycles and species, 0.56 of total root biomass was in the 0 to 0.1 m layer, 0.73 between 0 and 0.2 m, and 0.84 between 0 and 0.4 m. Regression analysis indicated that roots should be sampled to 0.4 m to account for 90% of the variation in roots to the 1.2 m depth. Net root production was estimated to be 495 and 753 g m-2 in cycle 1 for WW-Spar and Caucasian, respectively, and 366 and 388 g m-2 in cycle 2. Relative growth rates (RGR) of total plant biomass were similar in both grasses and increased linearly during each growing cycle to values between 0.01 and 0.02 g d-1 g-1. Increases in RGR early and late in a growing cycle were supported by increases in efficiency of the photosynthetic apparatus (unit leaf rate). Mid-cycle increases in RGR were more dependent on expansion in the size of the photosynthetic apparatus (leaf area ratio) as unit leaf rate remained constant during this time. In addition to physiological differences found in earlier studies, this study suggested that variations in drought performance between these 2 grass species may also be related to morphological differences, primarily the tendency of WW-Spar to partition more of its root biomass to lower depths in the soil profile than Caucasian and perhaps the much greater crown or basal area of WW-Spar compared to Caucasian.
    • Causes and Economic Effects of Mortality in Livestock Guarding Dogs

      Lorenz, J. R.; Coppinger, R. P.; Sutherland, M. R. (Society for Range Management, 1986-07-01)
      We assessed causes of pre-senile mortality among working guarding dogs, and its effects on their management and cost. A population of 449 livestock guarding dogs in 31 states showed no differences in mortality due to breed or sex, but dogs working on open rangelands died more frequently (p<.001) than those working on farms or fenced ranches. Half of the farm dogs died before they reached 38 months of age, by which time nearly three-quarters of the open rangelands dogs had succumbed. Accidents accounted for over half the deaths, culling for inappropriate behavior accounted for one-third, and diseases for 9%. High accident and culling rates in young dogs substantially increased the cost of this predator control technique. However, we found 2 main areas where corrective measures can be applied: (1) increasing the awareness among producers that accidents are a main cause of deaths especially during the dogs' first 30 months of age; and (2) reducing the number of culls by improving the genetics of the dogs and by training producers to manage them.
    • Changes in Bacterial Populations in Wyoming Mountain Streams After 10 Years

      Hussey, M. R.; Skinner, Q. D.; Adams, J. C. (Society for Range Management, 1986-07-01)
      Streams of mountain watersheds in Wyoming were monitored to compare water quality data collected during 1971-72 with data collected during 1982. After 10 years there was little change in: (1) total coliforms, (2) fecal coliforms, (3) fecal streptococci, (4) plate counts at 35 degrees C, (5) total heterotrophic aerobic bacteria, (6) denitrifying bacteria, and (7) those organisms capable of reducing sulfate. Grazing management, recreation activities, and wildlife use of the watershed studied seem to be contributing a constant bacterial load to streams sampled by year and month during summer.
    • Cold-Temperature Germination of Elytrigia repens X Pseudoroegneria spicata Hybrids

      Young, J.; Evans, R. A.; Johnson, D. A.; Asay, K. H. (Society for Range Management, 1986-07-01)
      The successful establishment of perennial grass seedlings on Artemisia rangelands may depend on germination in the early spring at cold seedbed conditions. To ascertain the feasibility of selecting for germination at low temperatures in a hybrid population, seeds for 30 RS hybrid [Pseudoroegneria spicata (Pursh) Love × Elytrigia repens (L.) Nevski] lines were germinated under a wide range of constant or alternating temperatures. The hybrid populations were characterized in 11 different, but related germination responses to incubation temperatures based on discriminate analysis of seedbed temperatures. Germination at very cold incubation temperatures was markedly reduced in all populations compared to germination at more moderate temperatures. A range of 0 to 16% germination existed among the hybrids at very cold temperatures after 4 weeks incubation. At the very cold temperature regime, crested wheatgrass [Agropryon desertorum (Fisch.) Schult.] had 1% germination and intermediate wheatgrass [Thinopyrum intermedium (Host) Barkworth and D.R. Dewey] had 3% germination. At cold temperatures, germination of one hybrid line exceeded that of the wheatgrasses. At cold fluctuating temperatures, 13 and 22 hybrid lines had higher germination than intermediate and crested wheatgrass, respectively. Results of this study indicate a high potential of selection among these hybrid lines for germination in rangeland seedbeds under cold temperature regimes.
    • Comparative Infiltration Rates and Sediment Production on Fertilized and Grazed Blue Grama Rangeland

      Wood, M. K.; Donart, G. B.; Weltz, M. (Society for Range Management, 1986-07-01)
      This study determined the impacts of fertilization and livestock grazing on infiltration rates and sediment production. Infiltration rates and sediment production varied across years, depending on precipitation conditions, but were not different between fertilized and unfertilized rangeland within a year. Livestock production and stocking rates were 2 times greater on fertilized than on nonfertilized rangeland. Soil bulk density was only greater on the fertilized areas than the control at the end of the grazing period in 1982. Microtopography or roughness was not different between treatments. Increases in plant production mitigated any impacts from increased livestock numbers in fertilized areas.
    • Cubed Alfalfa Hay or Cottonseed Meal-Barley as Supplements for Beef Cows Grazing Fall-Winter Range

      Cochran, R. C.; Adams, D. C.; Currie, P. O.; Knapp, B. W. (Society for Range Management, 1986-07-01)
      A 2-year study evaluated the efficacy of supplements for beef cows grazing mixed grass prairie during the fall and winter. Cows were allotted to 3 treatments: (1) range forage only, (2) range forage plus 1.2-1.3 kg alfalfa cubes hd-1 d-1, and (3) range forage plus .9 kg cottonseed meal-barley cake hd-1 d-1. Supplements were fed daily to provide approximately 50% of crude protein requirements. Treatment effects did not depend (P<0.10) on year for independent variables evaluated. Although weather conditions differed among years, observed changes in weight and condition score were similar (P<0.10) for both years. Supplemented cows gained weight; but supplement type did not influence weight gains. In contrast, unsupplemented cows displayed significant weight loss. Supplemented cows either maintained or slightly increased in body condition during the fall-winter period. However, body condition of unsupplemented cows decreased (P<.05) compared with condition of supplemented cows. Supplementation with alfalfa cubes resulted in similar performance compared with supplementation with cottonseed meal-barley cake. Supplementing diets of wintering range cows with feeds high in protein improved performance compared with no supplementation.
    • Effects of Temperature and Presowing Treatments on Showy Menodora Seed Germination

      Fulbright, T. E.; Flenniken, K. S. (Society for Range Management, 1986-07-01)
      Low seed germination is a problem in establishment of showy menodora (Menodora longiflora Gray). Objectives of this study were to determine the effects of temperature, light, and presowing treatments on showy menodora germination. Scarified and untreated seeds were germinated at 5/15, 10/20, 15/25, 20/30, 25/35, and 30/40 degrees C (12 hour/12 hour) with 12 hours of light at the warmer temperature or complete darkness. Seeds were subjected to: (1) chemical scarification with concentrated (18.0 mol liter-1) H2 SO4, 2.9 mol liter-1 H2O2, or 0.7 mol liter-1 NaOCl, (2) a hot (80 degrees C) water soak, and (3) nicking with a razor blade. Percent germination and germination rate were highest at 20/30 degrees C. The highest percentage of abnormal seedlings occurred for mechanically scarified seeds at 5/15 degrees C. Light did not affect germination at 15/25, 20/30, and 30/40 degrees C, but enhanced germination at 5/15, 10/20, and 25/35 degrees C. Scarification enhanced percent germination and germination rate at all temperatures. At 20/30 degrees C, nicking seeds with a razor and a 3-minute soak in 0.7 mol liter-1 NaOCL resulted in 81 and 78% germination, respectively, of 1-year-old seeds, compared to 53% for untreated seeds. These results indicate that showy menodora seeds should be scarified by mechanical means or with 0.7 mol liter-1 NaOCL and planted when average daily minimum/maximum soil temperatures are about 20/30 degrees C for maximum germination.
    • Efficacy of Zinc Phosphide and Strychnine for Black-Tailed Prairie Dog Control

      Uresk, D. W.; King, R. M.; Apa, A. D.; Linder, R. L. (Society for Range Management, 1986-07-01)
      Three rodenticide treatments, zinc phosphide (prebaited) and strychnine (both with and without prebait), were evaluated immediately following treatment for efficacy of controlling black-tailed prairie dogs in western South Dakota. Active prairie dog burrows were reduced 95% with zinc phosphide, 83% with strychnine (prebaited), and 45% with strychnine without prebait. Zinc phosphide was the most effective in reducing active burrows of prairie dogs.
    • Estimating Leaf Area of Big Sagebrush from Measurement of Sapwood

      Ganskopp, D.; Miller, R. (Society for Range Management, 1986-07-01)
      Wyoming big sagebrush (Artemisia tridentata subsp. wyomingensis) plants were destructively sampled in May 1984 in southeast Oregon to examine the applicability of the pipe model theory to an arid land shrub. This theory proposes that total leaf area or leaf biomass of a plant is limited by the amount of conducting tissue available to service the leaves. Basal sapwood areas were measured for 20 Wyoming big sagebrush plants and correlated with the biomass and leaf area of the supported foliage. Additional samples of leaves were collected over a 12-month period to evaluate fluctuations in leaf weight to leaf area relationships. Basal sapwood area of sagebrush stems was a reliable indicator of foliage biomass or leaf area (r2=0.95). Leaf area to weight relationships fluctuated significantly throughout the year with the most substantial changes occurring during the growing season. Although this species is an evergreen, the dynamic nature of foliage production and morphology demands intensive seasonal sampling to accurately predict leaf areas.
    • Foaling Rate and Survival of Feral Horses in Western Nevada

      Siniff, D. B.; Tester, J. R.; McMahon, G. L. (Society for Range Management, 1986-07-01)
      Foaling and mortality rates of known-age feral horses equipped with radio transmitters were obtained in 1981 and 1982 for 2 areas in Nevada. These data showed considerable annual variation. In one area, 45% of the mares produced foals in both years while only 10% produced foals in the other area. Foal mortality ranged from 2% to 33%. Both the highest mortality (33% in 1981) and the lowest (2% in 1982) occurred in the same area. The cause for this apparent inconsistency was unknown. The highest age-specific reproductive rates occurred in 5 to 10 year-old mares.
    • Optimal timing of investments to control honey mesquite

      Torell, L. A.; McDaniel, K. C. (Society for Range Management, 1986-07-01)
      A general economic model to analyze optimal timing of brush control treatments and other range improvements was developed. The model was then applied to investments to control mesquite (Prosopis glandulosa Torr.) invading native rangeland in the Rolling Plains of Texas. Although a positive grass response from mesquite control would be anticipated for 5 years under average conditions, the economic optimum retreatment schedule is only 4 years. An increase in beef price shortens the optimal retreatment schedule, while an increase in treatment cost lengthens the optimal retreatment schedule. Implementing brush control treatments during a year favorable for a high rate of top kill is an important economic consideration.
    • Seasonal Variation in Above-Ground Annual and Perennial Phytomass of an Arid Rangeland in Libya

      Gintzburger, G. (Society for Range Management, 1986-07-01)
      An Aristida pungens-Retama retam rangeland in the arid Jeffara plain in Libya produced 2,000 and 950 kg (dry matter) ha-1 of net above-ground phytomass with 200 mm and 171 mm of rainfall during the 1977/78 and 78/79 growing seasons, respectively. Annual plants contributed 460 and 300 kg (dry matter ha-1) in the 2 seasons, respectively. Perennial shrubs lost their 1978 winter-spring aerial production during the long 1978 summer and dry winter when grazable forage was most needed. In contrast, spring production of annual plants remained available and grazable until late summer. Settlement of shepherds' families on site is not advised as the dead standing phytomass (270 kg dry wood ha-1) may be rapidly exhausted for fuel consumption, leading to wind erosion problems on presently fixed sand dunes.
    • Short Duration Grazing in Central New Mexico: Effects on Infiltration Rates

      Weltz, M.; Wood, M. K. (Society for Range Management, 1986-07-01)
      The objectives of this study were to determine the influence of short duration grazing, continuous grazing, and grazing exclusion on infiltration rates on 2 range sites in southcentral and eastcentral New Mexico. Short duration grazing had no beneficial effect on the hydrology of 2 different range sites. The terminal infiltration rates of both short duration grazing systems, after the cattle had grazed the area, were about one-half the terminal infiltration rate of the same area before the cattle grazed the area. Cattle distribution within the different grazing treatments had no effect on infiltration rates at 0.4, 0.8, and 1.2 km away from water for a moderate continuous, heavy continuous, and a short duration grazing system. Moderate continuous grazing was superior to heavy continuous grazing and short duration grazing, based on the hydrologic variables evaluated.
    • Some Impacts of 2,4,5-T on a Mesquite Duneland Ecosystem In Southern New Mexico: A Synthesis

      Gibbens, R. P.; Herbel, C. H.; Morton, H. L.; Lindemann, W. C.; Ryder-White, J. A.; Richman, D. B.; Huddleston, E. W.; Conley, W. H.; Davis, C. A.; Reitzel, J. A. (Society for Range Management, 1986-07-01)
      Two aerial applications of 2,4,5-T [2,4,5-trichlorophenoxy) acetic acid] were applied to 3,634 ha of mesquite (Prosopis glandulosa Torr. var. glandulosa) dunelands in southern New Mexico. Herbicide residuals; herbaceous plant production; soil microorganisms; insect, small mammal, and bird populations; cattle weights; travel; time budgets; and diets were studied on the treated area and an adjacent, untreated area. Stem kill of mesquite ranged from 17 to 66%. Herbicide residuals in soils and plant tissue on the treated area dissipated within a single season. Herbaceous plant production was measured for 5 years on a small area sprayed in 3 consecutive years and on untreated rangeland. Production was greater on the sprayed than on the unsprayed area for the first 3 years and was about the same on both areas for the next 2 years. Microbial populations were not numerically different between treatments but dehydrogenase activity and CO2 evolution were greater in dunal than interdunal soils. Numbers of tenebrionid beetles (Coleoptera: Tenebrionidae) did not differ between treatments. More mesquite leaf tiers (Tetralopha euphemella) were found on the sprayed area than on the untreated area. Population statistics for small mammals were similar on both treatments. More bird species were found on untreated than on sprayed areas. Cattle weights, travel, and time budgets did not differ between treatments and there were only minor differences between treatments in cattle diet quality. The sprayed area supported over twice as many AUM's of grazing as the untreated area in the first 3 post-treatment years. In the second post-treatment year, cattle liveweight produced was 2.9 and 1.5 kg/ha on the sprayed and untreated areas, respectively. Overall, the 2,4,5-T treatment caused relatively minor perturbations in measured ecosystem components.
    • Threshold Requirements for Burning Downed Honey Mesquite

      McPherson, G. R.; Wright, H. A. (Society for Range Management, 1986-07-01)
      Forty-one headfires were burned on 0.1-ha test plots on 2 west Texas study sites in the spring of 1984. The purpose of these burns was to develop a prescription for predicting whether downed honey mesquite will be consumed by a prescribed fire. It was found, using regression analysis and discriminant analysis techniques, that critical variables for predicting ignition and combustion of downed honey mesquite are: (1) windspeed, (2) stem moisture content, (3) stem diameter, and (4) proportion of green fuel in the fuel bed. Threshold values for ignition were 6 km/hr windspeed, 6% stem surface moisture content, 5 cm stem diameter, and 15% green:total fine fuel. Threshold values for sustained combustion were 15 km/hr windspeed, 6 cm stem diameter, and 6% stem moisture content at 1.25 cm below the stem surface. A prescription for burning downed honey mesquite was developed.
    • Tolerances of Sagebrush, Rabbitbrush, and Greasewood to Elevated Water Tables

      Ganskopp, D. C. (Society for Range Management, 1986-07-01)
      Knowledge of the effects of saturated soils and flooding on Wyoming big sagebrush (Artemisia tridentata wyomingensis), green rabbitbrush (Chrysothamnus viscidiflorus), and black greasewood (Sarcobatus vermiculatus) can enhance our understanding of their distribution. The responses of these 3 species to elevated water tables were studied on 4 contours bordering an expanding lake in southeast Oregon during the 1983 and 1984 growing seasons. When plants were initially selected for study, contours were 0, 10, 20, and 40 cm above the lake surface. Continued expansion of the lake flooded the lower contours and elevated the water tables under the upper contours. Wyoming big sagebrush rapidly succumbed to surface flooding and elevated water tables within 10 cm of the surface. Green rabbitbrush behaved similarly, but responses lagged about 1 week behind sagebrush. Black greasewood tolerated surface flooding for 40 days before effects were apparent. Water tables within 25 to 30 cm of the surface had no effect on greasewood. Given adequate topography and water supplies, water spreading techniques could be used to control Wyoming big sagebrush and green rabbitbrush.