• A Water-Balance, Climate Model for Range Herbage Production

      Wight, J. R.; Hanks, R. J. (Society for Range Management, 1981-07-01)
      A crop production model was modified and evaluated for application to native grassland ecosystems. The model effectively predicted annual herbage production for range sites near Sidney, Montana, and Mandan, North Dakota, where model-predicted yields were within 10% of field measured yields for 12 of the 15 test years. Soil water content, as calculated by the model, was also closely correlated (r2=0.91) with field measured soil water. Model inputs include beginning soil water content, daily precipitation, and an estimate of potential evapotranspiration. Soil water content, evaporation, and transpiration are calculated daily. Yields are determined as a function of the actual to potential transpiration ratio. Availability of input data, relative simplicity, and low computer costs make this model a viable tool for both research and resource management.
    • Ability of Desert Rodents to Find Buried Seeds

      Johnson, T. K.; Jorgensen, C. D. (Society for Range Management, 1981-07-01)
      There were significant variations in how many caches of buried Indian rice grass (Oryzopsis hymenoides) seeds were found by Dipodomys microps, Dipodomys ordii, Microdipodops megacephalus, Perognathus formosus, Perognathus longimembris, Perognathus parvus, Peromyscus maniculatus, and Reithrodonotomys megalotis. Success ranged from that of P. maniculatus and R. megalotis, that failed to find any buried seeds in dry sand, to P. formosus, that found 57.5% of the seeds buried at 0.6 cm, to M. megacephalus that found 50% buried 1.3 cm deep. Peromyscus maniculatus and P. parvus found more buried seeds as the soil moisture was increased.
    • An In-Depth Examination of the Philip Equation for Cataloging Infiltration Characteristics in Rangeland Environments

      Jaynes, R. A.; Gifford, G. F. (Society for Range Management, 1981-07-01)
      The objective of this study was to investigate the use of Philip's equation coefficients (which have, in theory, direct physical meaning) to characterize infiltration on rangelands. It was found that a least squares regression approach to estimating Philip equation parameters (S and A) essentially reduces A, and perhaps S, to empirical coefficients. However, the Philip equation does provide a model that fits infiltrometer data reasonably well and reflects significant differences between infiltration curves. The effects of land management and temporal variables (e.g., soil moisture, season) may be associated with changes in S and A for particular sites. Indexing of infiltration curves by model coefficients allows for infiltrometer data from different researchers to be pooled and provides a basis for simulation modeling of infiltration and runoff on small watersheds. Coefficients are tabulated for a variety of rangeland plant communities for easy reference by practicing rangeland hydrologists. Researchers who present infiltration data in the future are urged to represent their data, at least in part, in the form of S and A coefficients to expand results tabulated from this study.
    • Carbohydrate Reserve, Phenology, and Growth Cycles of Nine Colorado Range Species

      Menke, J. W.; Trlica, M. J. (Society for Range Management, 1981-07-01)
      Nine Colorado range species were studied for two consecutive years to relate the carbohydrate reserve status with phenological stage of development and current annual growth, including leaf, twig, or seedstalk length, or plant height. The species were four-wing saltbush (Atriplex canescens), antelope bitterbrush (Purshia tridentata), little rabbitbrush (Chrysothamnus vicidiflorus), fringed sagewort (Artemisia frigida), scarlet globemallow (Sphaeralcea coccinea), blue grama (Bouteloua gracilis), western wheatgrass (Agropyron smithii), James' cryptantha (Cryptantha jamesii), and pricklypear cactus (Opuntia polyacantha and rhodantha in a mixed stand). Seasonal total nonstructural carbohydrate (TNC) reserve cycles were related to phenological stages of development. Growth of all species appeared to be stimulated by late-summer or fall precipitation. Growth was found to be related inversely to carbohydrate reserve storage. Fourwing saltbush and antelope bitterbrush had typical V-shaped annual carbohydrate reserve cycles, and little rabbitbrush had a somewhat flat or extended V-shaped cycle. Fringed sagewort, scarlet globemallow, and western wheatgrass had flat or extended V-shaped cycles and maintained low reserves for more of the growing season than any of the species with typical reserve cycles. Blue grama was the only species that exhibited a narrow V-shaped cycle. The shape of the seasonal TNC cycle appeared to be a good screening tool for assessing the relative effects of defoliation on different plant species. Plants that replenished reserves rapidly after spring draw-down and regrowth periods, and minimized the part of the growing season with low reserve status, were least affected by defoliation and recovered rapidly from severe defoliation.
    • Disagreement among Investment Criteria—A Solution to the Problem

      Workman, J. P. (Society for Range Management, 1981-07-01)
      Three standard investment criteria, benefit-cost ratio (B/C), internal rate of return (IRR), and present net worth (PNW), are commonly used for economic evaluation of range improvements. Unfortunately, as commonly calculated, these three criteria often yield contradictory selections when choosing between two or more possible range improvement projects. Disagreements among the three criteria are caused by differences in project lives and initial investments (size), along with failure to recognize explicitly the rate of return foregone on alternative investments. This paper demonstrates that when projects are normalized for non-uniform lives and differences in size, the three investment criteria yield identical project selections. Correct project selection by B/C requires normalization for non-uniform size, while the IRR calculations must be normalized for differences in both project size and expected life. The following procedure is recommended for selecting an optimum combination of projects from among numerous alternatives: (1) Rank projects by B/C. (2) Select best projects first until available capital is exhausted. (3) Perform PNW side calculations to verify the accuracy of the selected project combination.
    • Early Succession in Aspen Communities Following Fire in Western Wyoming

      Bartos, D. L.; Meuggler, W. F. (Society for Range Management, 1981-07-01)
      Aspen clones in varying degrees of deterioration were burned in northwestern Wyoming in an attempt to regenerate the site. Large numbers of aspen suckers are necessary to perpetuate these stands under current heavy ungulate use. Sucker numbers doubled the second year after burning and by the end of the third year had returned to near preburn levels of 15,000-20,000 suckers per hectare. This slight increase in sucker numbers is probably not sufficient to regenerate the stands under current browsing pressures. Total understory production declined the first year following fire and then increased to 3,600 kg/ha the second year-almost double preburn conditions. Production decreased the third year to about one-third greater than before burning. Forb and grass production increased and shrubs decreased as a result of burning. Fireweed (Epilobium angustifolium) was the largest post-fire contributor to total understory production.
    • Effects of a Wet-Dry Seed Treatment on the Germination and Root Elongation of "Whitmar" Beardless Wheatgrass under Various Water Potentials

      Kastner, W. W.; Goebel, C. J.; Maguire, J. D. (Society for Range Management, 1981-07-01)
      Seeds of Whitmar beardless wheatgrass (Agropyron spicatum f. inerme Beetle) were allowed to imbibe water at 20 degrees C for 24 hours, followed by air-drying at room temperature for 24 hours. Seeds were then placed in slanted-plate containers held at 20° C to measure germination and root elongation under water potentials of -0.3, -7.5, and -15 bars. Seed treatment significantly accelerated germination and root elongation under a water potential of -0.3 bars, with some acceleration occurring at -7.5 bars. Treatment did not accelerate growth activity under a water potential of -15 bars.
    • Effects of Cattle Grazing on Mountain Meadows in Idaho

      Leege, T. A.; Herman, D. J.; Zamora, B. (Society for Range Management, 1981-07-01)
      Vegetation changes which occurred during 12 years of protection from grazing were documented in mountain meadows of north-central Idaho. Plant composition changes were evident on all five sites studied, whereas herbage production was significantly less on the grazed than ungrazed areas at two of the sites. Season-long grazing by cattle has apparently been responsible for decreasing production and retarding plant succession. A change in grazing systems would likely increase the carrying capacity for herbivores.
    • Effects of Fall Clipping or Burning on the Distribution of Chemical Constituents in Bluebunch Wheatgrass in Spring

      Willims, W.; Bailey, A. W.; McLean, A.; Kalnin, C. (Society for Range Management, 1981-07-01)
      We examined the effects of fall clipping or burning on chemical constituents and their distribution in bluebunch wheatgrass the following spring. The study was made in both a big sagebrush-bluebunch wheatgrass and a Douglas fir-bluebunch wheatgrass community. The concentration of mineral constituents (nitrogen, phosphorus, calcium and magnesium) was lower while the concentration of fibrous constituents (acid detergent fiber, neutral detergent fiber and lignin) was higher in leafy material at the top of the plant. In the big sagebrush community, the differences among treatments were generally greater in the lower segments of plants. Generally, the mineral constituents increased while the fibrous constituents decreased from the control to the clipped to the burned treatment. The treatment effect was more variable in plants from the Douglas fir community.
    • Forage Quality of Western Wheatgrass Exposed to Sulfur Dioxide

      Milchunas, D. G.; Lauenroth, W. K.; Dodd, J. L. (Society for Range Management, 1981-07-01)
      Effects of three exposure levels of SO2 (55, 100, and 170 micrograms m-3) on the nutritive value of western wheatgrass were investigated. Significant increases in plant sulfur content were observed, both with time and level of SO2 exposure. Plant ash content paralleled the trends observed for sulfur concentrations. Nitrogen concentrations in western wheatgrass were not affected by SO2 treatments. The increased plant sulfur content and decreased N:S ratios across treatments did not significantly affect forage digestibility as measured by in vitro digestible dry matter.
    • Grazing Systems: Their Influence on Infiltration Rates in the Rolling Plains of Texas

      Wood, M. K.; Blackburn, W. H. (Society for Range Management, 1981-07-01)
      Water infiltration rates into soils after 30 min in shrub canopy areas and in shortgrass interspaces on the Rolling Plains were similar across grazing treatments of heavy and moderate stocking, continuous grazing; rested and grazed deferred-rotation; rested and grazed high intensity, low frequency (HILF); and two live-stock exclosures which had been grazed for 20 years. The mid-grass interspace infiltration rates for the deferred-rotation treatments approached rates in the exclosures and exceeded rates in the heavily stocked, continuously grazed, and grazed HILF pastures. Infiltration rates in the HILF grazing treatments were similar to those of the heavily stocked, continuously and moderately stocked continuously grazed pastures. Infiltration rates in the rested HILF pasture were similar to those of the deferred-rotation pastures; however, the grazed HILF pasture had rates lower than the deferred-rotation pasture rates or rates of the exclosures. Aggregate stability, organic matter content, mulch, standing crop, bulk density, and ground cover significantly influenced infiltration rates.
    • Plot Delineation with a Pin-and-Chain

      Baker, R. L.; Pearson, H. A. (Society for Range Management, 1981-07-01)
      The pin-and-chain is currently being used to delineate sampling plot boundaries in Southern forest-range where conventional rigid plots would be impractical. The pin-and-chain method can be used for delineating both circular and rectangular plots.
    • Rangeland Seeder Development Using Semicircular Seedbox and Auger Agitator Seed Metering Concept

      Wiedemann, H. T.; Cross, B. T. (Society for Range Management, 1981-07-01)
      A rangeland seeder featuring a semicircular seedbox and auger agitator mounted to heavy-duty frame has proven reliable and durable under rough rangeland conditions. The experimental seeder reduces the variability in metering fluffy seed due to the improvement in design. Satisfactory metering of slick seed was accomplished with a commercial, cup-feed mechanism. Flexing, runner openers prepared and placed seed in a furrow without undue mechanical breakage while traversing logs, stumps and other debris left after rootplowing. The features of the experimental seeder increase the potential for seeding brush-infested rangeland because of improved reliability and less need for costly clean-up of brush debris.
    • Responses of Annual Range Grasses and Legumes to Comparable Applications of Manurial and Inorganic Fertilizers

      Jolley, L. W.; Raguse, C. A. (Society for Range Management, 1981-07-01)
      The use of cattle manure as an alternative to commercial inorganic fertilizer for annual rangelands was investigated, using mixtures of annual range grasses and legumes grown in pots containing a range soil known to be low in nitrogen and phosphorus and marginal in sulfur. Equivalent applications were made of N, P, and S over a wide range of levels (ca 100-1,200 kg/ha N, 23-276 kg/ha P, and 17-200 kg/ha S equivalents) with the N:P:S ratios of the inorganic fertilizer treatments adjusted to match those of the manure. All levels of both fertilizer types were applied either soil-incorporated or surface-broadcast. Plants were grown in greenhouse and outdoor environments, harvested twice, and separated into grass and legume components. Total yields and grass vields were higher for inorganic fertilizer. Clover yields were higher in the manure treatments, and in the outdoor environment, and increased from the first to the second harvests. Yields generally increased from first to second harvests and were higher in the outdoor environment. Mode of application had little effect on either yield or grass:legume ratio. Where economically feasible and available, the use of manures on rangeland may be justified, especially where enhancement of a legume component of the vegetation is desired.
    • Seasonal Vegetative Establishment and Shoot Reserves of Eastern Gamagrass

      DeWald, C. E.; Sims, P. L. (Society for Range Management, 1981-07-01)
      Seasonal vegetative establishment and shoot reserves of eastern gamagrass were studied at Woodward, Oklahoma. Single shoots and compound shoots were separated from parent plants and field transplanted twice monthly from January 1977 through September 1978. Shoot reserves were estimated by measurements of mass and percent new growth under etiolation, percent dry matter, and amount and percent total nonstructural carbohydrate (TNC). Etiolated growth, percent dry matter, and TNC were greatest during the winter dormant season and least during May and June. Stand establishment from vegetative propagation followed these same trends, indicating the importance of shoot reserves to vegetative propagation. Etiolated growth followed the same seasonal trends as TNC in shoots but had higher values, indicating that reserves other than carbohydrates measured in the TNC analysis may be important in new shoot growth of eastern gamagrass. Single shoots with high dry weights contained greater amounts of reserves than shoots with low dry weight sampled during the same period. Stand establishment was higher for compound than for single shoots from late June through September, apparently because compound shoots weighed more and contained more reserves than single shoots. Shoots of eastern gamagrass transplanted during the winter dormant season resulted in 90-100% establishment. Vegetative propagation could become an important means of establishing eastern gamagrass if suitable field transplanting equipment were developed. Eastern gamagrass has the potential to become a leading forage producer and engineering research to develop suitable propagation equipment is justified.
    • Streambank Erosion and Ungulate Grazing Relationships

      Buckhouse, J. C.; Skovlin, J. M.; Knight, R. W. (Society for Range Management, 1981-07-01)
      Streambank erosional patterns have been studied for 3 years (1 year of calibration and 2 years of active grazing treatment) on the Starkey Experimental Forest and Range in the Blue Mountains of northeastern Oregon. Livestock grazing use at the rate of 3.2 ha/AUM (8 acres/AUM) has not accelerated streambank degradation on Meadow Creek. Most erosion occurred during wintering periods and this erosion has been independent of grazing season treatments. It appears that high runoff and occasional ice flows are the most significant factors in bank cutting on this stream.
    • The Effect of Slide and Frequency Observation Numbers on the Precision of Microhistological Analysis

      Holechek, J. L.; Vavra, M. (Society for Range Management, 1981-07-01)
      The number of slides and frequency observations per slide required for microhistological analysis was determined. Slides should be prepared so that at least 20 frequency observations are recorded per slide. When five slides were prepared per sample, reasonable estimations were obtained for species comprising 20% or more of the diet. Minor and trace species in the diet were poorly estimated indicating a large number of slides are needed for adequate precision.
    • The Oxalate, Tannin, Crude Fiber, and Crude Protein Composition of Young Plants of Some Atriplex Species

      Davis, A. M. (Society for Range Management, 1981-07-01)
      Oxalate, tannin, crude fiber, and crude protein contents were determined in 11 introduced Atriplex species and four species native to western North America that might be browsed by wildlife and livestock. Atriplex species of foreign origin resembled domestic species in content of oxalate, tannins, crude fiber, and crude protein, with averages and range similar to those of A. canescens. These foreign species could fit into a range ecosystem to improve the quality and quantity of different browse species.