Journal of Range Management, Volume 52 (1999): Recent submissions
Now showing items 1-20 of 98
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Journal of Range Management, Volume 52, Number 3 (May 1999)Society for Range Management, 1999-05-01
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Journal of Range Management, Volume 52, Number 4 (July 1999)Society for Range Management, 1999-07-01
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Journal of Range Management, Volume 52, Number 1 (January 1999)Society for Range Management, 1999-01-01
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Journal of Range Management, Volume 52, Number 2 (March 1999)Society for Range Management, 1999-03-01
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Journal of Range Management, Volume 52, Number 5 (September 1999)Society for Range Management, 1999-09-01
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Yield and quality of warm-season grasses in central TexasWarm-season perennial bunchgrasses frequently are used for hay and grazing in central Texas. We compared 6 alternative grasses with 2 more commonly grown species ['Ermelo' weeping lovegrass, (Eragrostis curvula (Schrad.) Nees var. curvula Nees) and 'Selection-75' kleingrass (Panicum coloratum L.] on 2 soils during 2 years. Grasses were transplanted into field plots at Stephenville and Temple, Tex. 1993 and harvested 3 times in 1994 and 1995. Weeping lovegrass and 'WW-B.Dahl' old world bluestem [Bothriochloa bladhii (Retz) S.T. Blake] were the highest yielding (P < 0.05) grasses and averaged 9,350 and 7,630 kg dry matter ha(-1) in 1994 and 1995, respectively. 'Irene' tufted digitgrass (Digitaria eriantha Stued.) and kleingrass produced similar (P > 0.05) yields (6,560 and 6,340 kg dry matter ha(-1)). Experimental line 409-704 buffelgrass [Cenchrus ciliaris L. syn. Pennisetum ciliare (L.) Link], 'Carostan' flaccidgrass (Pennisetum flaccidum Greisb.), 'Palar' Wilman lovegrass (Eragrostis superba Peyr.), and P.I. 269961 Oriental pennisetum (Pennisetum orientale Rich) yielded less than 3,000 kg dry matter ha(-1) at Stephenville and were invaded by weeds. Tillers per plant generally explained most of the yield differences as plant density was held constant. Ermelo lovegrass and WW-B.Dahl old world bluestem produced 2 to 3 times more tillers plant(-1) than other grasses. Concentrations of neutral detergent fiber were higher (P < 0.05) in digitgrass and the lovegrasses than in other grasses (39 vs 36% of dry matter). These data indicate that WW-B.Dahl old world bluestem and Irene tufted digit-grass should be useful in forage-livestock systems in central Texas.
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Yield and feeding of prairie grasses in east-central AlbertaInformation on the yield of grasses as the plants mature is useful to optimize grazing potential and quality hay production. The objectives of this study were to compare the yield and feeding value of 11 common prairie grasses over 2 yearly cycles of growth and determine which of the grasses may require supplementation to meet nutrient requirements of grazing cattle. Dry matter yield (DM), crude protein (CP), acid detergent fiber (ADF), calcium (Ca), and phosphorus (P) values were obtained for brome (Bromus inermis [L.]), creeping red fescue (Festuca rubra [L.]), crested wheatgrass (Agropyron cristatum [L.] Gaertn), intermediate wheatgrass (Agropyron intermedium (host) Beauv), meadow foxtail (Alopecurus pratensis [L.]), orchardgrass (Dactylis glomerata [L.]), pubescent wheatgrass (Agropyron trichophorum Link. richt), streambank wheatgrass (Agropyron riparium Scriba &Smith), slender wheatgrass (Agropyron trachycaulum Link Malte), tall fescue (Festuca arundinacea Schreb), and timothy (Phleum pratense [L.]) at weekly intervals from June to September, in 1992 and 1993. Most grasses reached maximum yields at week 8 in 1992 (drought year) and week 12 in 1993 (normal year). Herbage mass yields (g/0.25m2 at week 8 in 1992 (highest to lowest yielding) were crested wheatgrass (235), intermediate wheatgrass(210), pubescent wheatgrass(173), brome(161), slender wheatgrass(152), meadow foxtail(114), Tall fescue(110), timothy(101), orchardgrass(83), creeping red fescue(56), and streambank wheatgrass(50). Herbage mass yields pattern of the grasses in 1993 was similar to that in 1992 except for crested wheatgrass and brome which ranked first and fourth in 1992 but ranked fifth and second, in 1993, respectively. Quality declined in all grasses as they matured. The average CP content of grasses declined from 24% to 13% in 1992 and from 21.5% to 12.1% in 1993 but were adequate to meet crude protein requirements of growing, pregnant or lactating grazing cattle. The Ca levels in all grasses were adequate for all classes of cattle on pasture but the low P levels of 0.11% in both years indicate that growing, pregnant or lactating cattle grazing on these pastures would require P supplementation.
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Western juniper expansion on adjacent disturbed and near-relict sitesWe determined rates of western juniper (Juniperus occidentalis spp. occidentalis Hook.) density and cover change during the period 1951 to 1994 at 3 adjacent sites with nearly identical elevation, slope, aspect, soils, plant communities, and climate, but different land-use histories. The 3 sites are located in central Oregon at the confluence of the Deschutes and Crooked Rivers. Two of the sites are typical of central Oregon rangelands in that they have a history of anthropogenic disturbance including active fire suppression and domestic livestock grazing. The third site is a relict mesa that is a protected Research Natural Area and has experienced minimal anthropogenic impacts. We used large scale aerial photography to determine cover and density of western juniper in 1951, 1956, 1961, 1972, 1982, and 1994. We found that western juniper density and cover during the last 4 decades increased at all sites, with changes on the relict site similar to those on one of the disturbed sites. We suggest that even though 2 of the traditionally cited causes of western juniper expansion since the late 1800s (altered fire regimes, domestic livestock grazing) may have contributed to expansion on our disturbed sites, these mechanisms can not explain expansion on the near-relict mesa. Further, we examined climatic changes since 1900 in the region and concluded that the data did not fully support a climate-driven mechanism for the expansion. In seeking to explain western juniper expansion on semiarid rangelands, we suggest that all potential causal mechanisms (e.g., fire history, biological inertia, climate, domestic grazing, atmospheric CO2 enrichment) be considered.
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Viewpoint: The role of drought in range managementDrought is an ambiguous term, subject to expectation and the weight of emphasis on meteorological, agricultural, hydrological and socio-economic dimensions. Uncertainty associated with the identification of drought often results in a lagged response in reducing stocking rates. This delay reduces vegetation cover, increasing the potential for accelerated erosion following the drought. The long-term consequences of accelerated erosion are a reduction of soil depth, a decline in soil structure and a decrease in infiltration rate and water storage capacity. Less water stored on a site hastens the onset of plant stress, effectively increasing the perceived frequency and consequences of drought. Management and policy tools must improve the integration of economic and ecological aspects of drought-induced de-stocking decisions, especially by incorporating the long-term irreversible costs of erosion.
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Viewpoint: The range utilization concept, allocation arrays, and range management scienceThe transition of range utilization from a qualitative concept in the early years of range management to a quantitative concept in today's range management science has been problematic. This paper (1) evaluates the origins, confoundings, and interpretations of range utilization in range management science, (2) presents an explicit allocation array of variables to replace the range utilization concept, and (3) examines the role of range utilization specifically, and management science generally in the present and future message of the Society for Range Management, and in range management science.
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Viewpoint: Implications of spatial variability for estimating forage useEstimates of forage use are often the basis for important management decisions (e.g., determining carrying capacity and setting stocking rates). Using both hypothetical and field data, we examine the impacts of rangeland spatial heterogeneity and various analysis protocols on estimates of forage use. When using the paired-subplot method, we recommend that the size of caged and uncaged subplots accommodate local heterogeneity to ensure accurate forage use estimates. We further recommend that the type of analysis procedure be determined by the context of the question; phytomass differences when an investigation is herbivore-focused, and relative utilization for plant community studies. All investigations of forage use should employ (field original, or untransformed) data to assess natural variability in forage production and to minimize the degree of confoundment between forage use and spatial heterogeneity. When analyzing these data, non-directional, 2-tailed statistical tests are recommended, particularly in arid (and thus, spatially variable) environments, to avoid bias in the estimate and to facilitate reliable interpretation of the data.
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Viewpoint: Delineating ecological sitesBoth the Society for Range Management's (1995) Task Group on Unity in Concepts and Terminology (UCT) and the Natural Resources Conservation Service (1997) have recommended use of the ecological site as the fundamental land unit for evaluation of rangeland condition and trend. While the ecological site concept may be relatively straightforward. in practice the spatial definition of ecological sites within a management unit can prove problematic. This paper presents the use of readily available digital information in a GIS frame-work to delineate ecological sites within a pinyon-juniper/sagebrush semi-desert dominated landscape in Central Utah. An existing model of pre-Euroamerican pinyon-juniper woodland dynamics was combined with the site classification to evaluate landscape dynamics. We also created a map of landscape pattern of potential utility to land managers. The mapping capabilities of GIS offer a simple and remarkably adaptable technique for visual modeling of landscape pattern to assist in meeting a wide array of land management objectives. However. the "objective" delineation of ecological sites must be recognized as being necessarily based on a priori user-selected criteria.
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Viewpoint: Benefits and impacts of wildlife water developmentsResource managers in the western United States have long assumed that water was a key limiting factor on wildlife populations in arid habitats. Beginning in the 1940s-1950s, state and federal resource management agencies initiated water development programs intended to benefit game species and other wildlife. At least 5,859 such developments have been built in 11 western states. Most state wildlife management agencies in the western United States have ongoing wildlife water development programs that vary greatly in extent. Ranchers and range managers also have developed water sources for livestock, many of which also are used by wildlife. Recently, critics have suggested that wildlife water developments have not yielded expected benefits, and may negatively impact wildlife by increasing predation, competition, and disease transmission. Based upon a comprehensive review of scientific literature, we conclude that wildlife water developments have likely benefitted many game and non-game species, but not all water development projects have yielded expected increases in animal distribution and abundance. Hypothesized negative impacts of water developments on wildlife are not supported by data and remain largely speculative. However, our understanding of both positive and negative effects of wildlife water developments is incomplete, because of design limitations of previous research. Long-term, experimental studies are needed to address unanswered questions concerning the efficacy and ecological effects of water developments. We also recommend that resource managers apply more rigorous planning criteria to new developments, and expand monitoring efforts associated with water development programs.
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Use of livestock and range management practice in UtahDespite large efforts to generate and extend management innovations for rangeland operators, little is known about the degree to which practices are used. We determined what influenced use of 26 management practices among 340 permittees using data from a mailed survey. Five, co-dominant socioeconomic groups of permittees were identified by cluster analysis: "Large-Scale Operators," 2 types of traditional "Ranchers," and 2 types of "Hobbyists." The main concern across groups was losing access to public land, and coping strategies overall included passivity (64%), intensification of private-land use (27%), and enterprise diversification (5%). Across all groups the 4 highest use rates uniformly occurred for livestock cross-breeding (92%), livestock supplementation (80%), planting improved forages on private land (76%), and interaction with extension personnel (73%). The 4 lowest rates (3 to 12%) occurred for use of futures markets, range-trend monitoring on private land, estrus synchronization, and short-duration grazing (SDG). Groups varied in use of feed and financial consultants, prescribed fire on private land, forward contracting, and controlled grazing systems other than SDG, with Large-Scale Operators tending to use these the most. Larger operation size and higher level of formal education and income for managers were positively associated with using more practices. Hobbyists tended to use practices the least. Practices which were less complex, clearly linked to animal production, potentially more cost-effective, and had greater compatibility with operational goals were favored. Socioeconomic groups and coping strategies have utility for better targeting research and extension. Understanding why some seemingly beneficial practices are rarely used requires improved communication with rangeland operators.
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Total nonstructural carbohydrate trends in Chinese tallow rootsChinese tallow (Sapium sebiferum L. Roxb.) was introduced to the United States from China in the mid to late 1800s and has since naturalized throughout much of the southern U. S. Tallow continues to invade a wide variety of habitats, but control efforts have been inconsistent. We related root total nonstructural carbohydrate (TNC) levels and phenological development in Chinese tallow over an annual cycle to determine optimal timing for control treatments. Six phenological stages were recorded; (1) dormancy, (2) bud break, (3) leaf development, (4) seed formation, (5) seed maturation, and (6) leaf fall. Tallow root TNC concentrations varied by phenological stage (P<0.001), where concentrations were highest (P<0.05) during leaf fall (60.72%) and lowest during leaf development (41.11%) and seed formation (36.71%). Chinese tallow root TNC concentrations increased during the period of seed maturation until leaf fall. If foliar applied herbicides are delivered during this period of downward translocation, effective tallow control may be observed.
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Technical Note: Test of observer variability in measuring riparian shrub twig lengthMeasurement of riparian shrub twig length before and after use should yield a useful utilization index. A first step towards determining utilization is measurement of twig length. This study appraised variability between 15 observers for measuring dormant season twig length on riparian alder (Alnus incana (L.) Moench) shrubs. Ten streamside shrubs were selected on which 5 branches consisting of 5 twigs each were tagged below the fifth twig for a total of 250 twigs. Fifteen experienced people independently measured twigs on the same day after instruction in the method. Data were analyzed by hierarchical analysis of variance for length of twigs by branches, by shrubs, and by observers. Variation among observers within a branch was about twice the size of variability among shrubs and represented 20% of the total variation. Items contributing to observer variability were measurement of dieback, selecting the twig end or live bud for measurement, inclusion of short lateral leaf stubs in measurements, and selection of a crotch from where the twig is measured. These results clearly illustrate major difficulties in trying to measure riparian shrub utilization.
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Technical Note: Nitrogen and phosphorus in runoff from 2 montane riparian communitiesIt was hypothesized that the type and height of riparian vegetation would affect its ability to filter and retain inorganic nitrogen (nitrate-nitrogen (NO3(-)-N), ammonium-nitrogen (NH4(+)-N), and inorganic phosphorus (phosphate-phosphorus (PO4(-3)-P)). A rotating boom rainfall simulator was used to evaluate 2 montane riparian communities as filters for removing NO3(-)-N, NH4(+)-N, and PO4(-3)-P nutrients from sediment laden overland flow water. One riparian community was characterized by Kentucky bluegrass (Poa pratensis L.) and tufted hairgrass (Deschampsia caespitosa (L.) Beauv.), while the second community was dominated by beaked sedge (Carex rostrata Stokes) and water sedge (Carex aquatilus Wahl.). Three vegetation height treatments were evaluated: control (natural condition), moderate treatment (clipped to 10-cm height and clipped material removed), and heavy treatment (clipped to ground level, clipped material removed, and litter vacuumed up). A 10-m wide riparian buffer zone was an efficient filter as about 84% NO3(-)-N and 79% PO4(-3)-P was removed from the applied water and sediment. However, there were no consistent differences among specific vegetation height treatments or communities in the removal of N and P nutrients.
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Stream channel and vegetation responses to late spring cattle grazingA 10-year riparian grazing study was conducted on a cold, mountain meadow riparian system in central Idaho in response to cattle grazing-salmonid fisheries conflicts. Six pastures were established along Stanley Creek to study the effects on riparian habitat of no grazing, light grazing (20-25% utilization), and medium grazing (35-50%) during late June. Stream channels narrowed, stream width-depth ratios were reduced, and channel bottom embeddedness decreased under all 3 grazing treatments as the area responded to changes from heavier historic grazing use. Streambank stability increased and streamside willow communities (Salix spp. L.) increased in both height and cover under all 3 treatments. Plant species richness increased on both streamside and dry meadow areas during the years of grazing and moderate drought. The numbers of species receded to near original levels in the ungrazed and light grazed pastures in 1996, a wet post-grazing year, primarily due to a decrease in forb species. Streamside graminoid height growth was similar among treatments after 1 year of rest. Most measurements of streamside variables moved closer to those beneficial for salmonid fisheries when pastures were grazed to 10 cm of graminoid stubble height; virtually all measurements improved when pastures were grazed to 14 cm stubble height, or when pastures were not grazed. Many improvements were similar under all 3 treatments indicating these riparian habitats are compatible with light to medium late spring use by cattle.
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Stocker cattle response to grazing management in tallgrass prairieThe effects of stocking rate and grazing method on performance of yearling beef cattle grazing tallgrass prairies in north-central Oklahoma were evaluated from 1989 to 1994. Pastures dominated by big bluestem [Andropogon gerardii Vitman], little bluestem [Schizachyrium scoparium (Michx.) Nash], and indiangrass [Sorghastrum nutans (L.) Nash], were allocated to either short duration rotational or continuous stocking methods and stocking rates ranging from 52 animal-unit-days (AUD) ha(-1) to 90 AUD ha(-1). Steers grazed the units from late April to late September. Precipitation was above average during the study period. Live weight gain per head was higher under continuous stocking than rotational stocking at all stocking rates. At 52 AUD ha(-1), individual gains under rotational stocking were 11% less than under continuous stocking. At 90 AUD ha(-1), individual gains under rotational stocking were decreased by 20%. Measurements of steer diets and forage standing crop suggest the reduction in weight gain was due to reduced forage intake under rotational stocking. Live weight gain per hectare increased with stocking rate and was higher with continuous stocking at all stocking rates. Net returns per hectare increased as stocking rate increased for both stocking methods but were lower for rotational stocking at all stocking rates. Variable costs per head would have to decrease by 24 to 34% under rotational stocking to equalize net returns between the 2 grazing methods. Unless the decline in gain per head can be reduced or eliminated, there is no economic incentive to implement rotational stocking under the conditions of this study.
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Spotted knapweed, forb, and grass response to 2,4-D and N-fertilizerHerbicidal control of spotted knapweed (Centaurea maculosa Lam.) on rangeland in the western United States has been most effective using residual herbicides, such as picloram (4-amino-3,5,6-trichloropicolinic acid). However, when residual herbicides cause concerns in riparian areas and for non-target forbs, management practices that use herbicides with lower soil persistence need to be developed. The objective of this study was to quantify the interaction between 2,4-D (2,4-Dichloro-phenoxyacetic acid, dimethylamine salt) and N-fertilizer on spotted knapweed, other forbs, and grass density and biomass. Five 2,4-D rates (0.0, 0.6, 1.1, 1.6, and 2.2 kg ai ha-1) and 5 N-fertilizer rates (0, 50, 100, 150, and 200 kg ha-1) were applied to 2 spotted knapweed infested rangeland sites in a factorial combination arranged in a randomized-complete-block design during the summer of 1996 in Montana. Spotted knapweed, other forb, and grass density and biomass were measured at peak standing grass crop in 1997 and analyzed using analysis of variance. Spotted knapweed density and biomass at Rock Creek were reduced 50% and 65%, respectively, by 2,4-D of treatments of 1.1 kg ai ha-1 or greater. Spotted knapweed biomass was slightly increased by N-fertilizer at 200 kg ha-1. Grass density increased by about 50% when treated with 2,4-D of 1.1 kgai ha-1 or greater N-fertilizer did not affect grass density or biomass. At Hyalite Creek, 2,4-D at 0.6 kg ai ha-1 reduced spotted knapweed density by 30%, and rates greater than 0.6 kg ai ha-1 reduced it by 75%. Spotted knapweed biomass was reduced by 75% at all herbicide rates tested. N-fertilizer and 2,4-D interacted to increase grass density at Hyalite Creek; however, grass biomass was not affected. At Rock Creek, neither 2,4-D nor N-fertilizer affected forbs. At Hyalite Creek, 2,4-D and N-fertilizer interacted to increase aster (Aster eatonii [Gray] Howell) biomass. Death camas (Zigadenus venenosus Wats.) biomass was increased by N-fertilizer addition. Combining N-fertilizer with 2,4-D may increase long-term control of spotted knapweed when residual herbicides cannot be used. Application of 2,4-D at the bud stage of spotted knapweed growth will provide some control of spotted knapweed without affecting early season forbs.