• Cutting height effects on wetland meadow forage yield and quality

      Dovel, R. L. (Society for Range Management, 1996-03-01)
      Research was conducted to determine the effect of clipping height on forage yield and quality of 3 wetland meadow plant associations. Bluegrass-clover (Poa spp. and Trifolium spp.), grass-sedge (Poa spp., Deschampsia caespitosa, and Carex spp.), and sedge (Carex spp.) associations were cut to stubble heights of 5, 10, or 15 cm in 1988, 1989, and 1990. Forage yield, herbage residue, crude protein (CP), and acid detergent fiber (ADF) were determined for forage harvested in June, July, and August. Forage yields of all associations increased as clipping height decreased. The majority of total forage produced for all associations was harvested in the June clipping. Herbage residue exceeded 1.4 Mg ha-1 for all clipping heights, dates, and associations. Average CP concentration of the bluegrass-clover, grass-sedge, and sedge associations was 12.1, 13.3, and 10.8%, respectively. The CP concentration of the 2 grass-dominated associations increased with decreasing clipping height, but clipping height effect on sedge association CP was not consistent across the growing season. Clipping date had a greater effect on forage CP concentration than did clipping height. Crude protein concentration of all associations increased from the June clipping date to the July clipping date and declined in August. Clipping height did not significantly affect ADF of the bluegrass-clover or grass-sedge associations. Sedge ADF decreased with increasing clipping height in the first clipping, but increased with increasing clipping height in the second and third clippings. Bluegrass-clover ADF increased in a linear fashion from 30.9% at the June clipping date to 36.1% at the August clipping date. In contrast, both the grass-sedge and sedge associations showed curvilinear responses to clipping date, increasing from June to July and then declining in August.
    • Draft requirements to fell junipers

      Wiedemann, H. T.; Cross, B. T. (Society for Range Management, 1996-03-01)
      An inexpensive method of tree felling is needed to precondition dense stands of mature junipers (Juniperus spp.) for the effective use of prescribed burning. The purpose of this research was to determine draft requirements to fell individual juniper trees at different striking heights. These baseline data are necessary to design an elevated chaining technique. Sites in Oklahoma with single-stemmed Ashe juniper (Juniperus ashei Buchholz) (N=40) and Texas with multi-stemmed redberry juniper (Juniperus pinchotii Sudw.) (N=45) were selected for evaluation. A horizontal breaking bar was cabled to an instrumented tractor drawbar for draft force determinations. Data from the drawbar loadcell were stored in a laptop computer data acquisition system. Maximum force to fell junipers was determined at striking heights of 0, 0.6, 0.9, and 1.2 m in Oklahoma and striking heights of 0, 0.6, and 0.9 m in Texas. Force to fell Ashe juniper trees at striking heights of 0, 0.6, 0.9, and 1.2 m averaged 149, 78, 50, and 38 kN, respectively. Striking trees at 0.9 m compared to 0 m (ground level) reduced the felling force by 67% and still uprooted 50% and severed 50% at ground level. With redberry junipers, felling force at striking heights of 0, 0.6, and 0.9 m averaged 81, 14, and 12 kN, respectively. At the striking height of 0.6 m, required draft was reduced by 84% compared to ground level striking, and 67% of the trees were severed at ground level and the remainder were uprooted. To predict force to fell a given size tree, draft was regressed on basal stem diameter in Ashe juniper or total basal stem area in redberry juniper. Based on these data, we concluded an anchor chain modified for elevated striking heights could substantially reduce the tractor drawbar draft for preconditioning of dense stands of juniper by chaining.
    • Effects of competition on the postfire recovery of 2 bunchgrass species

      DeFossé, G. E.; Robberecht, R. (Society for Range Management, 1996-03-01)
      The effect of competition on the postfire recovery of Festuca idahoensis Elmer and Agropyron spicatum (Pursh) Scrib &Smith, was examined under natural conditions. Thirty plants of each species were exposed to fire applied with a portable instrument system that allowed precise control of fire temperature and duration, so that all plants received statistically similar fire severity levels inside the meristematic crown region. Treated plants were subjected to different levels of competition by periodically removing all or part of the aerial biomass around a monitored bunchgrass plant. Soil water potential, soil temperatures, and plant productivity were determined at monthly intervals during the growing season for the different competition treatments. No significant mortality due to fire was observed for plants of either species. Although Festuca did show meristematic tissue damage after fire, regrowth that occurred within 15 days after fire was more rapid than for Agropyron. Only Agropyron plants without competition reached prefire productivity levels. Soil water potential was significantly more negative in plots with competition. Temperatures in the upper 10-cm of the soil profile were significantly higher in plots without competition. Competition reduced root production and also restricted aboveground productivity by approximately 70% for Agropyron and 115% for Festuca. The capacity of these species to survive fire appears to be related more to the micro-environmental conditions created following fire and to their capacity to compete for available soil water, than to the direct effects of fire on plant tissues.
    • Estimation of botanical composition of esophageal extrusa samples using near infrared reflectance spectroscopy

      Volesky, J. D.; Coleman, S. W. (Society for Range Management, 1996-03-01)
      The objective of this study was to evaluate the potential of near infrared reflectance spectroscopy (NIRS) for estimating botanical composition of esophageal extrusa samples. Spectral data were collected on 361 samples from fistulated sheep and cattle grazing native tallgrass range. Principal components analysis was used to identify a subset of 73 samples with spectral dissimilarity. These samples were microhistologically analyzed to determine botanical composition and were considered 'actual' for regression and calibration purposes. Thirty-six species (12 grasses, 22 forbs, and 2 sedges) were identified in the microhistologically analyzed samples. However, most accounted for less than 5% of the total diet. Additional pure calibration samples were obtained by feeding individual species to confined fistulated sheep. Initial regression analyses and predictions were made on 13 major species or species groups. Satisfactory prediction equations could only be developed for big bluestem andropogon gerardii Vitman) (r2 =0.61), and the total grasses (r2= 0.79) and total forbs (r2 = 0.79) groups. Addition of spectra from pure samples into the calibration set was beneficial. In general, valid predictions could not be made for individual species that constituted less than 10% of the sample and/or had a low frequency of occurrence in the calibration samples. The NIRS method offered acceptable precision and accuracy in the prediction of major botanical components and it would be practical and efficient because it reduces the number of samples that would have to be microhistologically analyzed.
    • Germination and root growth of 4 osmoconditioned cool-season grasses

      Mueller, D. M. (Society for Range Management, 1996-03-01)
      Establishment of grass species used in range reseeding should improve if germination time can be decreased. Osmotically controlling the hydration of seed so that germination processes proceed other than radicle emergence (osmoconditioning) can decrease germination time of many plant species. Growth chamber esperiments were conducted to evaluate effects of osmoconditioning at -1.5, -2.0, and -2.5 hlpa for 4,8,12,16, and 20 days on germination and root growth of ‘Flintlock’ western wheatgrass (Pascopyrum smithii (Rydb.) A. Löve) and ‘Vinall’ Russian wildrye (Psathyrostuchys juncea (Fischer) Nevski) and at -2.0, -2.5, and -3.0 hWa for 4, 8, 12, 16, and 20 days on ‘Nordan’ Crested wheatgrass (Agropyron desertorum (L.) Gaertn.) and ‘Tegmar’ intermediate wheatgrass (Agropyron intermedium (Host) Beauv.). A second study looked at germination time of seed from the same species conditioned at osmotic potentials and durations producing the shortest time to 50% germination (optimum conditioning) and air dried for 0, 1, or 7 days. Conditioned seed of Russian wildrye and western wheatgrass germinated 2 to 4 days faster, respectively than untreated seed. Optimum conditioning of seed from all 4 species produced seedlings with roots 20 to 67% shorter 4 days after germination than seedlings from untreated seed. Conditioned western wheatgrass seed continued to germinate faster than untreated seed after being air dried for 7 days. Slow root growth from conditioned seed may negate any benefits derived from rapid germination.
    • Grazing date and frequency effects on prairie sandreed and sand bluestem

      Reece, P. E.; Brummer, J. E.; Engel, R. K.; Northup, B. K.; Nichols, J. T. (Society for Range Management, 1996-03-01)
      A 5 year study was conducted during 1988-1992 to quantify the effects of grazing date and frequency on total organic reserves of prairie sandreed [Calamovilfa longifolia (Hook.) Scribn.] and sand bluestem (Andropogon hallii Hack.). Treatments consisted of mid-month grazing periods in (1) June, (2) July, (3) August, (4) October, (5) June and July, (6) June and August, (7) July and August, or (8) June, July, and August. Seasonal stocking rates were equal among treatments and divided equally over multiple grazing periods. Grazing treatments were applied to the same pastures during 4 consecutive years with yearling cattle and 4-7 day grazing periods. Mean tiller weight of etiolated initial-spring growth was used to estimate total organic reserves in the fifth year. Dormant season grazing in October was not different from 4 years of rest for either species. Total organic reserves in prairie sandreed decreased when paddocks were grazed in June or July regardless of the number of grazing periods per treatment. Reserves in sand bluestem were maintained by grazing once in June or August. Rotationally grazing pastures 2 or more times during June-August is least likely to maintain or increase total organic reserves in either species. Multiple grazing periods initiated in June reduced reserves by about 38% in prairie sandreed and 30% in sand bluestem. When stocking rates are similar to this study, deferment periods should be longer than 60 days after grazing in June to avoid measurable reductions in total organic reserves in both species. Periodic deferment of grazing until mid-August or later will be required to maintain simultaneously high levels of reserves in prairie sandreed and sand bluestem.
    • Harvest frequency and burning effects on mono-cultures of 3 warm-season grasses

      Cuomo, G. J.; Anderson, B. E.; Young, L. J.; Wilhelm, W. W. (Society for Range Management, 1996-03-01)
      Harvest frequency and burning can affect forage yield of monocultures of switchgrass (Panicum virgatum L.), big bluestem (Andropogon gerardii Vitman), and indiangrass [Sorghastrum nutans (L.) Nash]. Current information is based largely on results from mixed stands. A field experiment was established in 1986, and from 1988 to 1991 treatments were applied with burning in March, April, or May plus an unburned control. Growing-season yield was measured by harvesting 1 (June), 2 (June and July), or 3 (June, July, and August) times with unharvested control plots included. End-of-season standing crop from all plots was determined after plants became dormant. Treatments were applied to the same plots annually and were arranged in a split-split plot, randomized complete block design. The main plot was species, subplot was burn date, and sub-subplot was harvest frequency. Burning reduced yields (p<0.01), and yields were lowest in plots burned in May. Burning reduced yields of indiangrass most (57%) and big bluestem least (15%). In 1989, plots harvest- ed three times produced yields similar to plots harvested once for all species. By 1991, yields of plots harvested 3 times per growing-season were reduced (P=0.08) below those of plots harvested once. Yield response of species also varied across the study. Growing-season yields in 1991 were 113, 67, and 89% of 1989 yields for switchgrass, big bluestem, and indiangrass, respectively. Regardless of burning and harvest frequency combination, switchgrass produced as much or more herbage than the other species.
    • Importance of predation and germination on losses from the seed bank of calden (Prosopis caldenia)

      Lerner, P.; Peinetti, R. (Society for Range Management, 1996-03-01)
      Caldén (Prosopis caldenia) seeds not dispersed by animals sometimes constitute a considerable number of seeds to the seed bank which may contribute to the species' dissemination. The monthly change in the number of viable non-animal dispersed seeds was evaluated over a one-year period. We determined the percentage germination of seeds and the amount of predation by bruchid beetles to learn how these factors influence seed longevity. Forty eight bags containing 10 fruits were placed in 4 sites below caldén tree canopies at the time of shedding (March). To monitor seed losses we randomly removed 1 bag per site every 25-35 days during a year. At the time of shedding, fruits contained 29 seeds, 73 +/- 5.0% which were viable and 9 +/- 2.2% attacked by bruchids. Viability decreased to 33 +/- 22.3% one year later. Loss of viability was described by a polynomial quadratic (y = 70.12 + 0.0238 t-0.0004 t2 (r2= 0.62)). Bags with germinated seeds were observed beginning in November. Percentage germinated seed increased 4.8 +/- 3.7% in the last month of sampling. Consumption of seeds by bruchids also increased in November, but the effect was highly variable. In the last month of sampling (March in the following year), 35 +/- 18.0% of seeds were affected by bruchids. A predictive seed longevity model was developed considering climatic variables, but data were well described only until January (y = 81.50-0.097 time-3.94 precipitation (r2= 0.66)). Undispersed seeds had a high rate of decay and low germination. Longevity was strongly affected by bruchid attack.
    • Interrelationships of forage and steer growth dynamics on wheat pasture

      Pinchak, W. E.; Worrall, W. D.; Caldwell, S. P.; Hunt, L. J.; Worrall, N. J.; Conoly, M. (Society for Range Management, 1996-03-01)
      Little information is available comparing animal performance or stocking stability for different wheat (Triticum aestivum L.) cultivars. Wheat is annually planted on 10 million ha in the Southern Great Plains. Our objective was to determine the effects of wheat cultivars with different forage production potentials on the seasonal and total productivity of steers. 'Lancota' and 'NK Pro 812'(NK 812) were planted in September 1987 and October 1988 at the W.T. Waggoner Ranch in north Texas. Hereford steers (Bos taurus L.), 220 to 233 kg. were grazed from November 1987 to May 1988 and December 1988 to April 1989. Seasonal and total forage production and disappearance were affected (p<0.05) by season and year. Cultivar did not affect forage production and disappearance. Steer average daily gain (ADG), gain head-1, and gain ha-1 were significantly affected by year, season, year x season, and cultivar x season interactions. Steer gain ha-1 was lower (P<0.10) in year 2 than year 1 for both cultivars. Both gain head-1 and gain ha-1 were lower (P<0.10) on NK 812 than Lancota in year 2. Season long gain ha-1 followed similar trends to gain head-1. A season x year interaction (P<0.05) occurred because NK 812 matured earlier and was less winter hardy than Lancota. Across years steer ADG increased with herbage allowance up to 27.3 kg 100 kg BW-1 Day-1 and further increases in herbage allowance had limited effect on steer ADG. Yearly variation in environmental conditions had greater effects on steer performance and forage production than cultivar.
    • Karoobush defoliation in the arid Karoo

      Du Toit, P. C. V. (Society for Range Management, 1996-03-01)
      The relation was studied between the applied stocking rates and the degree to which sheep grazed stems of various karoobush species. A rule of thumb exists amongst farmers and research workers in the Karoo, that sheep graze stems of karoobushes with a diameter of 2 mm or less. This hypothesis was examined over a period of 3 years. The meetly grazed off stems of Pentzia spinescens Less. (doringkaroo) and Rosenia humilis (Less.) Bremer (blou perdekaroo), the most abundant forage species, were measured by sliding Vernier callipers. Estimates of grazeable dry matter, as used in the estimate of the current grazing capacity, is based on the separation of clipped dry matter into grazeable and non-grazeable material. This separation is based on the 2 mm criterion. The hypothesis that sheep voluntarily graze stems with a diameter of up to 2 mm was rejected. The stems of less palatable species are seldom grazed at 2 mm diameter, while grazed stems of paintable species are often thicker than 5 mm. It was established that sheep graze stems of the less palatable karoo bushes to a mean diameter of 1.4 to 1.6 mm. This impacts directly on the method in which dry matter production is estimated for the purposes of determining grazing capacity. The long term grazing capacity norm for this area is 30 ha large stock unit-1. Based on gain ha-1 data obtained from stocking rate trials, the grazing capacity is 33.4 ha large stock unit-1. The stocking rate: grazed stem relation yields an optimum grazing capacity figure of 32.5 ha large stock unit-1. This indicates that monitoring the grazed stems of appropriate species can be used to set grazing capacity limits or adjust stocking rates.
    • Productivity of Cenchrus ciliaris in relation to rain-fall and fertilization

      Rao, A. S.; Singh, K. C.; Wight, J. R. (Society for Range Management, 1996-03-01)
      Forage for livestock is always in short supply in the arid zone of India. Cenchrus ciliaris L. is one of the major forage grasses cultivated in this region. We studied its productivity in relation to rainfall and nitrogen (N) and phosphorus (P) fertilization in the Indian arid zone at Jodhpur during 1983 to 1992. Factorial combinations of 4 rates of N (0, 20, 40, and 60 kg ha-1) and 3 rates of P (0, 15, and 30 kg ha-1) were applied annually. Twenty kg N ha-1 was the most effective fertilizer treatment, increasing average annual forage yields from 942 to 1,785 kg ha-1 over the 10 year study with significant yield increases occurring in 7 of the 10 years. Yield responses to N rates greater than 20 kg ha-1 occurred only during the last 3 years of the study and then only at the 60 kg ha-1 rate with either 15 or 30 kg P ha-1. Yields reached maximum levels on both the nonfertilized and fertilized plots with between 180 and 250 mm of growing-season rainfall.
    • Seasonal changes of herbage biomass on the fescue prairie

      Willms, W. D.; Adams, B. W.; Dormaar, J. F. (Society for Range Management, 1996-03-01)
      Knowing the amount of herbage on rangeland is basic to management decisions related to livestock grazing. However, the amount of herbage available for grazing changes seasonally. Therefore, changes in herbage biomass were examined in different communities of the fescue prairie. The study was conducted at 2 sites in southwestern Alberta. In the Porcupine Hills near Stavely, changes in herbage biomass components were examined in 3 communities: rough fescue (Festuca campestris Rydb.), Parry oat grass (Danthonia parryi Scribn.)-Kentucky bluegrass (Poa pratensis L.), and Kentucky bluegrass-sedge (Carex spp.) by sampling at monthly intervals from April or May to late September. Observed trends among the rough fescue, Parry oatgrass-Kentucky bluegrass, and Kentucky bluegrass-sedge communities were, for peak current year's standing production, 398, 305, and 226 g m-2, respectively; for spring current year's standing production as a percent of its peak, 73, 50, and 35%, respectively; and for percent losses of total herbage biomass, from fall to spring, 24, 43, and 56%, respectively. In the foothills near Pincher Creek, the standing crop of grasses and fortes was sampled using paired subplots. One subplot was harvested in October and the other in April. Dry matter losses over winter averaged 27 and 58% for grasses and fortes, respectively. Of the 3 communities examined, production on the rough fescue community was the greatest, least dependent on precipitation during the growing season, and least susceptible to weathering losses and, therefore, had the greatest forage values. The Kentucky bluegrass-sedge community had the lowest forage values.
    • Seedbed and seeder options for old world bluestem establishment

      Berg, W. A.; Dewald, C. L.; Sims, P. L. (Society for Range Management, 1996-03-01)
      Seedbeds of graze-out wheatland and herbicide-killed wheat (Triticum aestivum L.) were evaluated as were use of a grass drill and the Woodward chaffy grass seeder for Old World bluestem (Bothriochloa ischaemum (L.) Keng) establishment. Seedings were made in 3 consecutive years in western Oklahoma. Steer grazing days on the seedbed treatments, seedling establishment, and second year grass herbage production were measured. Adequate stands were established in either seedbed. Economics favor the graze-out wheat seedbed treatment which produced an average of 189 steer grazing days ha-1 year-1. Adequate stands were established with either the grass drill or the Woodward seeder. Denser stands were usually established with the Woodward seeder—this was unexpected since it is a broadcast seeder. Results with the Woodward seeder are attributed to a requirement for very shallow planting of Old World bluestem and the protected environment of wheat drill furrows and wheat residue. Seedbeds of graze-out wheatland are recommended for Old World bluestem establishment in the Southern Plains.
    • Semi-arid warm-season grass yield and nutritive value in Argentina

      Stritzler, N. P.; Pagella, J. H.; Jouve, V. V.; Ferri, C. M. (Society for Range Management, 1996-03-01)
      The use of standing dead biomass, during the winter that was produced by warm-season grasses in the previous growing season by pregnant beef cows may be an alternative to grazing systems in the semi-arid Pampean Region of Argentina. This study, conducted over 2 years, 1990 and 1991, compared the winter forage quality produced during the previous growing season for 4 warm-season grasses; switchgrass (Panicum virgatum L. cv. Pathfinder), kleingrass (Panicum coloratum L.), tetrachne (Tetrachne dregei Nees) and weeping lovegrass (Eragrostis curvula (Schrad), Nees cv. Tanganyka). Five harvests of the summer growth started after the first frost, and were spaced evenly throughout the winter period. Changes in the standing crop of dry matter were measured and subsamples of forage were divided into leaf and stem fractions. Forage quality analyses included: crude protein (CP), in vitro dry matter digestibility (IVDMD), effective rumen degradability (ED), neutral (NDF) and acid (ADF) detergent fiber and lignin. Tetrachne dregei produced forage with a higher leaf:stem ratio and of generally higher quality, than the other species, although the differences were not always significant. Its CP content was marginally below the maintenance requirements of cows. Dry matter yield of tetrachne was lower than that of weeping lovegrass, but differences were only significant in 1990. Kleingrass generally was high in quality and dry matter yield, although it was the lowest in percentage of leaves of the 4 species evaluated. Switchgrass was the least productive; the nutritive value of its forage was low, comparable or lower than that of weeping lovegrass. The first harvest date was higher in nutritive value. Although the nutritive value of leaves and stems were not compared statistically, the leaves tended to be higher than the stems. Tetrachne dregei, the best of the species evaluated in this study, is a very promising warm-season grass, which could provide nutritious forage for winter grazing systems in the semiarid Pampean Region of Argentina.
    • Soil nutrients and salinity after long-term grazing exclusion in a flooding Pampa grassland

      Chaneton, E. J.; Lavado, R. S. (Society for Range Management, 1996-03-01)
      Soil organic C, total N, extractable P, and salinity were evaluated after 12-16 years of protection from grazing in 2 native grassland sites which differed in frequency of soil waterlogging in the Flooding Pampa of Argentina. We tested the hypothesis that flooding regime would affect the impact of grazing on soil chemical properties. We sampled soil to 10-cm depth in adjacent grazed and ungrazed plots in each site, and assessed the percentage dissimilarity (PD) in vegetation composition among pastures. Grazing condition significantly interacted with site (p<0.001) in affecting topsoil C, N, and salinity. Soil C and N were higher in grazed grassland (C = 4.8%; N = 0.42%) than in long-term exclosure (C = 3.7%; N = 0.35%) for the more frequently flooded, lowland site, hut did not vary between grassland plots in the upland site (C = 3.1%; N = 0.29%). Soil electrical conductivity (E.C.) was low in both ungrazed plots (< 2 dS/m), yet in grazed condition salinization was higher in the upland (E.C.= 6.85 dS/m) than in the lowland site (3.88 dS/m). Soil extractable P did not change in any consistent way with grazing treatment. Grazing apparently amplified differences in soil chemistry between lowland and upland sites, while differences in botanical composition between topographical positions were smaller for grazed (PD = 44 %) than for ungrazed (64 %) grassland. Moreover, contrasting responses between sites occurred for various soil parameters, whereas compositional differences between grazed and ungrazed plots were similar in each site (PD = 65%). Thus, soil-vegetation changes in response to grazing appeared to be loosely coupled in this rangeland ecosystem
    • Tallgrass prairie vegetation response to spring burning dates, fertilizer, and atrazine

      Mitchell, R. B.; Masters, R. A.; Waller, S. S.; Moore, K. J.; Young, L. J. (Society for Range Management, 1996-03-01)
      Tallgrass prairies provide an important source of hay and summer forage in eastern Nebraska. A study was conducted in 1989 and 1990 on 2 late seral tallgrass prairies near Lincoln and Virginia, Nebraska to determine if production of selected components of tallgrass prairie communities could be altered by burning (not burned, or burned in either early, mid-, or late spring)and applying fertilizer (0 and 67-23 kg N-P ha-1) and atrazine [6-chloro-N-ethyl-N'-(1-methylethyl)-1,3,5-triazine-2,4-diamine] (0 and 2.2 kg a.iha-1). Vegetation was harvested the year treatments were applied at about 30-day intervals starting in June and ending in August. Maximum big bluestem (Andropogon gerardii var. gerardii Vitman) accumulated standing crop (ASC) on unburned areas and areas burned in mid-spring occurred later in 1990 than in 1989. Burning in late spring 1989 maintained big bluestem ASC above 1,100 kg ha-1 through July, whereas big bluestem ASC declined below 840 kg ha-1 in July on areas where other burn treatments were applied. In 1990, big bluestem ASC exceeded 1,570 kg ha-1 in June on areas burned in early and midspring and exceeded 1,500 kg ha-1 in July on areas that were not burned or burned in mid- or late spring. From July to August 1990 big bluestem ASC declined below 730 kg ha-1 for all treatments except the late spring burn treatment where ASC was 1,340 kg ha-1. Burning in late spring reduced prairie dropseed [Sporobolus heterolepis (A. Gray) A. Gray] and tall dropseed [S. asper (Michx.) Kunth.] ASC by at least 67% in June 1990 compared to areas burned in early and mid-spring. Cool-season grass ASC at Virginia declined 86% in June when burned in late spring compared to areas that were not burned. Fertilization increased big bluestem ASC by about 23 and 29% in June and July. Vegetation response to atrazine was variable. Atrazine had a negligible effect on big bluestem ASC. Burning late seral tallgrass prairie in late spring increased big bluestem ASC later in the growing season and decreased cool-season grasses more effectively than burning earlier in the spring.
    • Viewpoint: Sustaining rangeland landscapes: a social and ecological process

      Huntsinger, L.; Hopkinson, P. (Society for Range Management, 1996-03-01)
      Sustaining rangeland ecosystems is as much a social process as an ecological one. It requires application of many of the same principles as those used in planning for wildlife reserves, but the tenets of conservation biology need to be applied to conserve social as well as ecological structural elements and processes. For some rangelands, a crucial element in a sustainable, culturally meaningful, and ecologically rich landscape is ranching, which is at once a collection of ecological processes and interactions, and an expression of human community. Results of several surveys and studies are used to highlight the "culture clashes" that occur at the ecological and social edges of landscape elements. Unfortunately, differing expectations of what conserved areas should be like has hindered the creation of alliances between environmentalists and ranchers that might prevent the degradation of the landscape by uncontrolled residential and urban development. In one California case, successful planning and alliance building led to the conservation of ranchlands. Zoning, conservation easements, political and financial support for the livestock industry, community leadership, and recognition of the heritage value of rural lifeways all played a part in this success. Similar patterns have been noted in other parts of the West. To conserve some of the most productive and biodiverse rangeland landscapes, ranching must not just be tolerated as a means to an environmental end, but valued and planned for, ecologically, socially, and economically. Rangeland professionals have an important role to play in the development of sustainable social relationships that support sustainable rangelands.