• Long-term plant community development as influenced by revegetation techniques

      Newman, G. J.; Redente, E. F. (Society for Range Management, 2001-11-01)
      A revegetation techniques study was initiated during the fall of 1976 in northwestern Colorado in a disturbed sagebrush (Artemisia tridentata Nutt.) community. The study included 2 irrigation treatments, three seed mixtures, 2 seeding techniques, and 2 fertilization treatments. Short-term results were published and conclusions were made regarding the initial success of each treatment. The objective of the current study was to determine the effects of each treatment on plant community production, species composition, and species diversity after 20 years of plant community development. Among irrigated plots, the native seed mixture produced greater aboveground biomass compared to an introduced mixture and a mixture of both native and introduced species (combination seed mixture). The native seed mixture also resulted in greater total species richness than the introduced mixture when averaging over all other treatments. Altered seeding rate ratios among life forms as well as altered seeding methods (drill versus broadcast seeding) did not significantly alter plant community development after 20 years. However, a single application of nitrogen and phosphorus significantly increased grass production on plots seeded to the combination seed mixture. All revegetation plots have remained grass-dominated. However, shrub biomass was greater in the native and combination mixtures than in the introduced mixture under initial irrigated conditions in part due to successful establishment and growth of four-wing saltbush (Atriplex canescens Pursh Nutt.). Thus, the seed mixtures evaluated in this study have resulted in distinctly different plant communities and demonstrate that such initial treatments can influence long-term plant community development on severely disturbed rangelands. Broadcast seeding a native seed mixture that has been irrigated for 2 growing seasons without fertilization appears to be an effective long-term combination of cultural revegetation practices.
    • Tracked vehicle impacts to vegetation structure and soil erodibility

      Grantham, W. P.; Redente, E. F.; Bagley, C. F.; Paschke, M. W. (Society for Range Management, 2001-11-01)
      There has been increasing concern that training on military lands results in excessive soil erosion, ecosystem degradation, and loss of sustainable training resources. Vegetation structure has been shown to play a role in soil surface stabilization by reducing shear stress caused by wind force. A study at the Idaho Army National Guard training facility at Orchard Training Area (OTA), Ida. assessed the effect of simulated M1A2 Abrams battletank maneuvers on grassland plant canopies and soil erodibility. The point-intercept method was used to estimate vertical vegetation structure before and after tracking. A portable wind tunnel was used to measure threshold wind speeds (TWS) associated with different numbers of tank passes and soil mass removed by wind. Results indicated that significant damage occurred to vertical vegetation structure as the number of passes increased. Threshold wind speed, an indicator of soil surface stability, significantly decreased with tracking and eroded soil mass significantly increased. Positive correlations existed between vegetation parameters and threshold wind speed. Soil loss was negatively correlated with vegetation parameters. Results indicated that the decrease of vertical vegetation structure led to a decrease in threshold wind speed. This decrease in threshold wind speed was the result of reduced soil surface protection by vegetation. Decreased surface protection also resulted in increased soil loss. Results from this work confirmed that vegetation plays a major role in reducing shear stress on the soil surface. Predictions for soil loss at Orchard Training Area resulting from the number of M1A2 passes are made using linear models. A critical tracking threshold of 4 passes was estimated based upon model output and average local wind speeds for Orchard Training Area.
    • Grazing impacts on soil nitrogen and phosphorus under Parkland pastures

      Baron, V. S.; Dick, A. C.; Mapfumo, E.; Malhi, S. S.; Naeth, M. A.; Chanasyk, D. S. (Society for Range Management, 2001-11-01)
      Because intensive grazing is new to the humid western Canadian parkland (prairies), there is little information available about its effects on soil N and P status. This study addressed the question of grazing intensity and pasture species effects on soil macronutrient status in a Typic Haplustoll at Lacombe, Alberta. Paddocks of smooth bromegrass (Bromus inermis Leyss.), meadow bromegrass (Bromus riparius Rhem.), and winter triticale (X Triticosecale Wittmack.), replicated 4 times, were subjected to 3 grazing intensities (heavy, medium, and light as defined by frequency and severity of defoliation) using yearling beef heifers. Nitrogen (N), P and K fertilisers were broadcast annually at 100, 22 and 42 kg ha(-1) during production years. The experiment was maintained on the same paddocks for 4 years. In the establishment year and in the third and fourth production years, soil samples were taken randomly from each paddock to a depth of 60 cm. Concentrations of nitrate-N (NO3-N), ammonium-N (NH4-N), mineral-N (the sum of NO3-N and NH4-N), total Kjeldahl-N, and extractable-P were determined in the 0-15, 15-30, 30-60, and 0-60-cm depths. Nitrate-N concentration was (1.7 to 2.4 times) greater for heavy than light grazed treatments for each soil depth increment and the amount of NO3-N in the 0-60 cm depth was 2.2 times greater than light paddocks. More NO3-N was measured under perennials than triticale (22.2 vs 13.6 mg kg(-1), respectively) at the 30-60-cm depth. Ammonium-N amount (0-60 cm) was greater in meadow bromegrass (30 kg ha(-1)) than in triticale (25 kg ha(-1)), but not smooth bromegrass paddocks for the 0-15-cm depth. Extractable-P concentration was greater in the 0-15-cm depth of heavy (154 mg kg(-1)) than in medium (138 mg kg(-1)) or light-grazed (127 mg kg(-1)) paddocks and was higher under meadow bromegrass than under triticale. Given the large amounts of NO3-N in the heavy paddocks, there is potential for loss through both leaching and denitrification. Differences among treatments for NH4-N, and P concentrations are not of particular concern environmentally, but are important from a fertility management point of view.
    • Climatic influences on recruitment of 3 subspecies of Artemisia tridentata

      Maier, A. M.; Perryman, B. L.; Olson, R. A.; Hild, A. L. (Society for Range Management, 2001-11-01)
      Previous research suggested that big sagebrush (Artemisia tridentata Nutt.) recruitment occurs in pulses consistent with favorable climatic conditions. In 1997, 75 stem sections were collected from 9 stands of each of the 3 subspecies of big sagebrush in Wyoming along elevation and climatic gradients. Annual growth rings were used to identify the year plants were established. Large cohorts of Wyoming big sagebrush (A. tridentata ssp. wyomingensis Beetle and Young) appeared in 1982, 1981, 1964, 1961, and 1955. Basin big sagebrush (A. tridentata ssp. tridentata Beetle and Johnson) cohorts flourished in 1991, 1986, 1985, 1982, and 1977. Mountain big sagebrush (A. tridentata ssp. vaseyana [Rydb.] Beetle) cohorts prospered in 1985, 1982, 1981, 1979, and 1974. Mean monthly precipitation and temperature records were compared to years with high and low recruitment using logistic regression models at 3 geographic scales (single-stand, regional, statewide). Wyoming big sagebrush recruitment was greatest in years with above-average December and January precipitation occurring after the first growing season (r2 = 0.10, 0.04, P < 0.05). Basin big sagebrush recruitment was most successful in years with above-average March, May, and June precipitation during the first growing season (r2 = 0.06, 0.09, 0.18, P < 0.05). Mountain big sagebrush recruitment was greatest in years with below-average February, April, and May precipitation after the first growing season (r2 = 0.03, 0.04, 0.04, P < 0.05). While variable precipitation patterns appear to contribute significantly to recruitment of big sagebrush, responses among the 3 major subspecies were quite variable. More complex models need to be developed to foster our understanding of the mechanisms affecting big sagebrush establishment.
    • Juniper encroachment in aspen in the Northwest Great Basin

      Wall, T. G.; Miller, R. F.; Svejcar, T. J. (Society for Range Management, 2001-11-01)
      In the northwest Great Basin, western juniper (Juniperus occidentalis subsp. occidentalis Hook.) is encroaching into aspen (Populus tremuloides Michx.) communities. There is a concern that aspen communities in this region are in a state of decline, but their status has not been documented. This study determined the timing, extent, and some of the effects of this expansion. Ninety-one aspen stands were sampled for density, canopy cover, age, stand structure, and recruitment of western juniper and aspen. Soils and tree litter beneath aspen and western juniper were collected to analyze the effects of western juniper on soils. Additionally, 2 large aspen complexes in southeast Oregon were intensively aged to determine disturbance (fire) frequencies. Western juniper encroachment peaked between 1900 and 1939 with 77% of all juniper trees sampled having been established during this period. Three-fourths of aspen stands sampled have established populations of western juniper. Twelve percent of aspen stands sampled were completely replaced by western juniper and another 23% dominated by western juniper. Average density of western juniper in aspen sites was 1,573 trees ha(-1). Seventy percent of aspen stands sampled had zero recruitment of new aspen. Aspen stands averaged 98 years old. There was an inverse correlation between aspen canopy cover and western juniper canopy cover. Soils influenced by western juniper had a higher C:N ratio, pH, salts, lime, and sulfate, and lower amounts of magnesium, iron, copper, and manganese. Aspen litter had a lower C:N ratio than western juniper litter. Two major aspen complexes sampled had even-age, 2-tiered even-age, and multiple-age aspen trees. The absence of presettlement juniper within all sampled aspen stands suggests fire was the primary stand-replacing disturbance in these northwest Great Basin aspen communities. The lack of fire coupled with aspen stand decadence and low recruitment levels will allow for the continued encroachment and replacement of aspen communities by western juniper in the northwest Great Basin.
    • Effects of prescribed fire on sand shinnery oak communities

      Harrell, W. C.; Fuhlendorf, S. D.; Bidwell, T. G. (Society for Range Management, 2001-11-01)
      Sand shinnery oak (Quercus havardii Rydb.) communities are shrublands extending from northern Texas and western Oklahoma southward into the Chihuahuan Desert. They are dominated by sand shinnery oak, a member of the white oak group. Structure and composition of sand shinnery oak communities in relation to natural disturbances, such as fire, have not been adequately investigated. The objectives of this study were to determine the influence of fire on shrub composition and vegetation structure of sand shinnery oak communities, and to determine the persistence of structural and compositional changes. Data were collected on Black Kettle National Grassland (BKNG) in western Oklahoma during the growing seasons of 1998 and 1999. Vegetation measurements included line transects, visual obstructions, heights, cone of vulnerabilities, shrub patch sizes, and shrub patch densities were used to estimate functional group canopy cover, shrub composition, and structure of sand shinnery oak communities. One growing season after fire, burned sand shinnery oak communities had significantly less shrub cover (P < 0.01) than unburned communities (38 vs. 51%). Height of vegetation was lower 1 and 2 growing seasons after fire (26 and 35 cm, respectively) (P < 0.05) than unburned communities (44 cm). Visual obstruction was lower the first (30%) and second (40%) year after fire (P < 0.01) compared to unburned communities (59%). Cone of vulnerability indicated significantly more open structure one growing season after fire. After 4 growing seasons, all measures of structure in burned communities were similar to those in unburned communities. We found no differences in composition of shrub species between burned and unburned sites (P = 0.55). Two fire events, 2 growing seasons apart, had less influence on vegetation structure than the initial fire. Sand shinnery oak communities appear to be highly resilient to periodic disturbance by fire. Prescribed fire is an effective tool for short-term alteration (< 3 growing seasons) of sand shinnery oak structure; however, rapid recovery following fire does not indicate any long-term changes in vegetation structure and composition.
    • Mesquite and grass interference with establishing redberry juniper seedlings

      Teague, W. R.; Dowhower, S. L.; Whisenant, S. G.; Flores-Ancira, E. (Society for Range Management, 2001-11-01)
      Excessive cover of juniper (Juniperus pinchotii Sudw.) reduces forage production, interferes with livestock management, and diminishes the watershed and wildlife habitat values of rangelands. We studied whether juniper seedlings were differentially suppressed in the presence of different grass species, and to what extent established mesquite (Prosopis glandulosa Torr.) trees facilitated or competed with establishing juniper seedlings. Seedlings growing with any of the grasses (RGR = 0.23 to 0.43 cm cm(-1)) grew significantly less than those with no grass competition (RGR = 0.72 cm cm(-1))(P < 0.01). Juniper seedlings grew significantly less in the presence of buffalograss (Buchloe dactyloides (Nutt.) Engelm.) (RGR = 0.23 cm cm(-1) than with either sideoats grama (Bouteloua curtipendula (Michx.) Torr.) (RGR = 0.43 cm cm(-1)) or tobosagrass (Hilaria mutica [Buckl.] Benth.) (RGR = 0.43 cm cm(-1))(P < 0.01). In contrast, juniper seedlings grew larger under intact canopies of mesquite (RGR = 0.99 cm cm(-1)) than in open grassland (RGR = 0.65 cm cm(-1))(P < 0.05) due in part to the greater nutrient availability (P < 0.05) under mesquite canopies. Juniper growing in sub-canopy positions with mesquite trees removed grew less (RGR = 0.84 cm cm(-1)) than those growing under mesquite canopies with root competition (RGR = 0.99 cm cm(-1))(P < 0.05). Juniper growing under intact mesquite canopies but without mesquite root competition, grew no better or worse (RGR = 0.93 cm cm(-1)) than those with mesquite root competition (RGR = 0.99 cm cm(-1))(P > 0.05), indicating that mesquite root competition with juniper is probably inconsequential. Since junipers grow mainly in fall, winter and spring when mesquite trees are dormant and leafless, the lack of competition may largely be due to these 2 species using resources at different times of the year. Greater nutrient availability beneath mesquite canopies, reduction of summer temperatures, and temporal separation of resource use clearly benefit juniper seedlings growing in the presence of mesquite. Managing for a vigorous grass component with low densities and cover of mesquite is the best way to limit the rate of invasion by juniper.
    • Adaptation of perennial triticeae to the eastern Central Great Plains

      Vogel, K. P.; Jensen, K. J. (Society for Range Management, 2001-11-01)
      The tribe Triticeae contains over 250 perennial species that are components of grasslands in the temperate and sub-arctic regions of the world and includes some of the world's most valuable forage and rangeland species. Many of these species had not been evaluated previously in the Central Great Plains, USA. A subset of the germplasm of the tribe Triticeae which included over 100 accessions of 55 different species was evaluated in a replicated, space-planted trial in eastern Nebraska during 1994-1996 to determine the survival and forage productivity of the accessions. The evaluated accessions were representative of perennial Triticeae genera and genomes. Perennial grasses of the Triticeae are based on the P, St, H, Ns, E, W, Y genomes and an unknown Xm genome(s). Triticeae that survived and had acceptable forage yields during the period of the trial were the Agropyron's-crested wheatgrasses (PP and PPPP genomes), Psathyrostachys-Russian wildryes (NsNs genomes), Thinopyron's-intermediate and tall wheatgrasses (EEEEStSt and EEEEEEStSt genomes), some Elymus (StStHH genomes), several Leymus (NsNsXmXm genomes), and Pascopyrum-western wheatgrass (StStHHNsNsXmXm genomes). Several Leymus species had not been evaluated previously in this region but showed considerable potential and merit additional evaluation, including L. chinensis, L. akmolinensi, L. racemosus, L. sabulosus, and L. secalinus. Species with only the H genome (Hordeum) and St genome (Pseudoroegneria) were not adapted to the region because of poor survival or low productivity. The study provides an example of how the rapidly emerging field of genomics can have practical applications to grasslands and rangelands.
    • Chemical composition and livestock ingestion of carob (Ceratonia siliqua L.) seeds

      El-Shatnawi, M. K. J.; Ereifej, K. I. (Society for Range Management, 2001-11-01)
      Pods and seeds from carob Ceratonia siliqua L. trees growing in Ajloun Mountainous forests and rangelands in Jordan were analyzed for their proximate analysis, Ca and P contents, and also the effects of ingestion of seeds by sheep and goat on the germination were investigated. Carob seed has hard seed coat dormancy, and seed scarification increased germination from 10.2% in non-scarified to 85.4% after scarification. Germination percentages for seeds that were ingested by sheep were 73.5, 61.8, 39.3, and 0.0% for ingestion periods of 24, 48, 72, and 96 hours, respectively; whereas, it was 56.8, 79.9, 50.1, 13.7, and 1.1% for seeds dispersed from goat after 24, 48, 72, 96, and 120 hours. Carob seeds contained higher amounts of protein, fiber, fat and Ca than deseeded pods. However, the latter contained more carbohydrates and P than seeds. Carob pods and seeds contained sufficient crude protein and energy to meet the maintenance and lactation requirements of ewes, but Ca and P contents were not adequate by themselves.
    • Suppression of annual bromes impacts rangeland: Animal responses

      Haferkamp, M. R.; Grings, E. E.; Heitschmidt, R. K.; MacNeil, M. D.; Karl, M. G. (Society for Range Management, 2001-11-01)
      Presence of annual bromes (Bromus spp.), introduced annual weedy grasses, can alter seasonal patterns of forage production and quality and require management changes for efficient use of infested rangelands. We determined biological impacts of the presence of brome by comparing livestock performance on brome infested rangeland to similar sites on which brome had been suppressed by autumn application of atrazine [6-chloro-N-ethyl-N'-(1-methylethyl)- 1,3,5-triazine-2,4-diamine] at 0.56 kg ha(-1) in 1992 and 1993. Each treatment was randomly assigned to three, 12-ha pastures. Vegetation was measured for 5 months (May to September) each year from 1993 to 1995. Each pasture was stocked with 8 crossbred steers of British breed origin (Bos taurus) from mid-May to mid-September 1993 and 1995 and to mid-August 1994. Initial body weights averaged 329 kg SD = 31 in 1993, 273 kg SD = 14 in 1994, and 272 kg SD = 21 in 1995. Brome suppression and environment influenced plant species in diets, diet quality, and livestock performance. Brome suppression reduced percentage of annual grasses in diets from 14% to 10%. Annual grasses were replaced in the diet by a variety of forb and grass species [western wheatgrass [Pascopyrum smithii Rydb. (Love)], and blue grama [Bouteloua gracilis [H.B.K.] Lag. ex Griffiths]], with specific replacement depending on year and month. Steer gains were increased from 0.92 to 1.04 +/- 0.02 kg head(-1) day(-1) (P < 0.02) and from 69 to 81 +/- 2.8 kg ha(-1) (P < 0.05) with brome suppression. This experiment demonstrated that improvement in livestock performance can be expected with the suppression of annual bromes on semiarid rangelands.
    • Suppression of annual bromes impacts rangeland: Vegetation responses

      Haferkamp, M. R.; Heitschmidt, R. K.; Grings, E. E.; MacNeil, M. D.; Karl, M. G. (Society for Range Management, 2001-11-01)
      Presence of invading annual bromes (Bromus spp.) can alter seasonal patterns of forage production and quality and require management changes for efficient use of infested rangelands in the Northern Great Plains. We studied biological impacts of the presence of brome by comparing brome infested rangeland to similar sites in which brome had been suppressed with autumn applications of atrazine [6-chloro-N-ethyl-N'-(1-methylethyl)- 1,3,5-triazine-2,4-diamine] at 0.56 kg ha(-1) in 1992 and 1993. Each treatment was randomly assigned to three, 12-ha pastures. Vegetation was measured for 5 months (May to September) each year from 1993 to 1995. Each pasture was stocked with 8 cross-bred steers (Bos taurus) from mid-May to mid-September 1993 and 1995 and to mid-August 1994. The forage base varied temporally by date and year, but generally was not less than 800 kg ha(-1). Brome suppression increased (P less than or equal to 0.05) crude protein concentration for western wheatgrass (Pascopyrum smithii Rydb. [Love]) in July (7.1 vs. 9.1%) and August (6.0 vs. 7.1%). With the variation in annual brome stands among years, as influenced by growing conditions, this experiment demonstrated that improvement in forage nutritional quality can be expected from suppression of annual bromes on semiarid rangelands.
    • Frequency grid—a simple tool for measuring grassland establishment

      Vogel, K. P.; Masters, R. A. (Society for Range Management, 2001-11-01)
      Simple, reliable tools are needed by land managers to quantify establishment success when seeding or re-seeding pastures or rangeland. A frequency grid was designed to measure seedling or plant establishment success for a single species, mixtures of species, or single species of a mixture. The frequency grid is a metal frame containing 25 squares (5 x 5) or cells and can be made from concrete reinforcing sheets that have 15 x 15 cm squares. When used, the frequency grid is either randomly or systematically placed within a seeded area. The number of cells containing 1 or more seeded plants are counted. The grid is then flipped, end-over-end, and the counts are repeated. The process is repeated until a total of 100 cells have been counted per sampling location within a seeded area. Counts can be directly converted into frequency of occurrence or stand percentages by dividing the number of cells that contain a seeded plant by 100. The process can be repeated at several locations within a seeded area to characterize establishment success. Multiplying frequency of occurrence percentages by 0.4 provides a conservative estimate of plant density (plants m(-2)). A single measurement of 100 frequency grid cells can be taken in less than 5 minutes. The frequency grid is inexpensive to make, requires minimal training, permits rapid measurements, and provides a meaningful estimate of plant density. The frequency grid has been used to document herbicide efficacy and seeding rates for use in grassland establishment in the central Great Plains and should be easily adaptable for use in other geographic regions.
    • Influence of off-stream supplements on streambanks of riparian pastures

      McInnis, M. L.; McIver, J. (Society for Range Management, 2001-11-01)
      Accelerated erosion of streambanks in grazed riparian pastures is of concern to land managers. We tested the hypothesis that providing cattle free-choice off-stream water and trace mineralized salt would lessen negative impacts of grazing on cover and stability of streambanks compared to pastures lacking these amenities, and may therefore reduce the potential of accelerated erosion. The study was conducted on Milk Creek at the Hall Ranch Unit of the Eastern Oregon Agricultural Research Center near Union, Ore. Three replications each of 3 grazing treatments were examined: (1) non-grazed control; (2) grazed with supplemental water and trace mineralized salt provided ("supplemented"); and (3) grazed with no supplemental water or salt ("nonsupplemented"). Each grazed pasture (approximately 12 ha) was stocked with cow-calf pairs for a mean stocking rate of 0.8 ha per AUM to achieve moderate grazing intensity of approximately 50% utilization of key forages. Pastures were grazed for 42 consecutive days during each of 2 years (1996-1997) beginning mid-July. Estimates of streambank cover ("covered" or "uncovered") and stability ("stable" or "unstable") were taken before (June) and after (September) grazing by examining 0.5 X 0.3 m plots placed on the greenline. Additionally, frequency of cattle hoof prints (number of plots with hoof prints/total number of plots) was measured as an indication of cattle presence in the greenline. Treatment effects were compared using one-way ANOVA. Streambank effects were consistent with observations of cattle distribution, with 26% of the streambank in supplemented pastures showing cattle presence (hoof prints), versus 31% for non-supplemented pastures. Off-stream water and salt attracted cattle into the uplands enough to significantly (p less than or equal to 0.05) reduce development of uncovered and unstable streambanks from 9% in non-supplemented pastures to 3% in supplemented pastures. An "erosion index" indicated no significant (p < 0.05) difference in potential accelerated streambank erosion between supplemented and non-supplemented pastures.
    • Nutritional dynamics of 7 northern Great Basin grasses

      Ganskopp, D.; Bohnert, D. (Society for Range Management, 2001-11-01)
      Land, livestock, and wildlife managers need to understand the nutritional dynamics of forages to sustain adequate growth and reproduction of their animals and/or assure equitable payment for forages. Despite a long history of livestock grazing in the northern Great Basin, seasonal and annual nutritional dynamics of many of the region's prominent grasses have not been described. We addressed this issue via monthly sampling of 7 cool-season grasses at 6 sites during 1992, a drier than average year having 86% of mean precipitation, and 1993, when above average precipitation (167% of average) occurred. With high yields predicted in 1993 (1,257 kg ha(-1)), the period of adequate forage quality [crude protein (CP) greater than or equal to 7.5%] was 83 days. In addition grasses did not respond to 97 mm of July-August rain with renewed growth. During 1992, a growing season beginning with less than average moisture, grasses responded to midsummer (49 mm) and fall (69 mm) rains by maintaining greater than 7.5% CP for 185 days. A diversity of grasses expanded the period of adequate forage quality especially during the lower than average moisture year. Giant wildrye (Elymus cinereus Scribn. Merr.), a deeply rooted grass, supported high quality forage until mid August, but did not respond to late-season moisture. In contrast, shallow rooted grasses like bottlebrush squirreltail (Sitanion hystrix (Nutt.) Smith), Sandberg's bluegrass (Poa sandbergii Vasey), and the winter-annual cheatgrass (Bromus tectorum L.) responded to summer or fall moisture with herbage ranging from 10 to 16% CP, thereby supplying high quality late-season forage. With most precipitation occurring in the northern Great Basin during colder months, livestock or habitat managers can, with a fair degree of certainty, predict yields from their pastures before turnout. With abundant moisture, managers will see the rapid deterioration of forage quality that occurs when grasses advance through their reproductive stages of phenology and generate a wealth of reproductive stems. The quandary arrives, however, when moisture accumulations are less than optimum. Fewer reproductive tillers develop, and our results show that timely precipitation may elevate desirable nutrient characteristics and expand the duration of adequate livestock/wildlife nutrition in the region. More long-term research is needed to decipher the mechanisms governing growth and development of rangeland grasses and to assess risks of various stocking alternatives when managers face uncertain yield and forage quality issues.
    • Adoption of Brush Busters: Results of Texas county extension survey

      Kreuter, U. P.; Amestoy, H. E.; Ueckert, D. N.; McGinty, W. A. (Society for Range Management, 2001-11-01)
      Changing landowner demographics and the increasing recognition that some quantity of woody plants is valuable for certain rangeland management objectives has led to increasing interest in selective brush management practices. Brush Busters is a collaborative extension/research program developed in response to this growing interest. A survey of Texas County Extension Agents-Agriculture was conducted in 1999 to determine their perceptions about the interest in and adoption of Brush Busters practices. Using 3 threshold photographs, Extension Agents representing almost 50% of the counties in the 9 Extension Districts surveyed estimated that 44, 34, and 49% of the total area of mesquite, juniper and pricklypear, respectively, could be treated using Brush Busters. They also indicated that over 405,000 ha (78% mesquite) were treated with Brush Busters methods between 1995 and 1998, but that this represented less than 7% of the potentially treatable area. In most Extension Districts, more time was spent disseminating information about Brush Busters methods than any other brush management method since 1995. Extension Agents indicated that Brush Busters has become popular because it is perceived to be an inexpensive, convenient, safe, effective and predictable method for controlling brush, and because user-friendly information is widely available. Our findings suggest that increasing the adoption rates of ecologically sound rangeland management technologies requires: (1) greater emphasis on developing and disseminating user-friendly messages to rangeland managers and Extension Agents; and (2) greater emphasis on short-term efficacy rather than the long term advantages of new technologies.