• Applicability of the Kostiakov equation to mixed prairie and fescue grasslands of Alberta

      Naeth, M. A.; Chanasyk, D. S.; Bailey, A. W. (Society for Range Management, 1991-01-01)
      The Kostiakov equation is of interest in rangeland hydrology because it is a simple 2 parameter equation with values of constants easy to determine from measured infiltration data, and because of its reasonable fit to infiltration data for many soils over short time periods. There is, however, some controversy in the literature regarding its applicability to rangelands. The Kostiakov infiltration equation was examined to determine its suitability to characterize infiltration on mixed prairie and fescue grassland ecosystems in Alberta, Canada. The infiltration data from double ring infiltrometers fit the Kostiakov equation very well. Of 26 regressions, 10 had an R2 over 0.95 while another 8 had an R2 over 0.90. The average R2 for all data at a site was 0.931 for mixed prairie, 0.857 for parkland fescue, and 0.938 for foothills fescue grassland. Changes in antecedent soil water and different grazing regimes altered the 2 equation parameters. Intercepts consistently declined with intensity and earliness in the growing season of grazing, although there were no consistent treatment trends with grazing. The Kostiakov equation is considered a good equation for infiltration in the 3 grassland ecosystems studied. Although parameter m had a narrow range of values for all 3 ecosystems and an average value from this study could be used, parameter a limits the equation and field testing is required for its determination.
    • Biomass productivity and range condition on range sites in southern Arizona

      Frost, W. E.; Smith, E. L. (Society for Range Management, 1991-01-01)
      Range condition is usually defined by similarity of current to climax or potential vegetation. It is often assumed that rangelands in low condition are biologically less productive than those in higher condition. The objective of this study was to determine if range condition (ecological status) is related to total productivity or to forage production for livestock. Adjacent areas along fencelines representing differences in range condition were sampled in 58 locations. These comparisons represented 31 different range sites across southern Arizona. Weight by species of above-ground peak standing crop current year’s growth of vegetation was estimated using the dry-weight-rank/comparative yield methods. Range condition was rated with Soil Conservation Service range site descriptions. Species were classified as forage or non-forage to estimate forage available for cattle. In 75-85% of comparisons of good condition sites to fair condition, good to poor, and fair to poor, total current year’s standing crop did not differ significantly. Where differences were significant, productivity was not consistently more on the high condition class. Forage production, however, was more from the stand in the higher condition class in about 213 of the comparisons. We concluded that in southern Arizona rangelands in higher condition (higher seral) classes usually produce more forage for cattle than lower condition classes on the same range site. Nevertheless, it is not usually true that total biomass productivity on low condition range is less than the same range site in higher condition.
    • Blue grama response to Zn source and rates

      White, E. M. (Society for Range Management, 1991-01-01)
      Surface-applied zinc (Zn) in range with claypan soils could increase herbage production, but the Zn concentration could become toxic to the crown and roots of blue grama (Bouteloua grucilis). Metallic Zn, ZnCl2, and Zn chelate were applied in the greenhouse to the soil surface of pots with blue grama to determine the rate that would be toxic and the effect of Zn source on toxicity and herbage Zn content. Metallic Zn (dust, 30- and 40-mesh) was not toxic at rates below 0.40 g Zn kg soil-1, but Zn chelate was toxic and ZnCl2 at the 0.40 g Zn rate was toxic initially. After 2 years growth, salt was leached and herbage yields were not significantly different for different sources. Herbage Zn increased with increasing application up to about 0.9 g Zn kg-1. ZnCI2, applied to plants that were not Zn deficient, decreased growth; and half the plants died at rates of 2 g Zn kg soil-1. Herbage from the 2-gm rate had 7.4 g Zn kg-1. DTPA-extracted soil Zn increased with increasing applications but not at the same rate for different sources. Metallic Zn or ZnCl2, if applied at reasonable rates, is a satisfactory Zn source, but high rates of Zn chelate cause soil dispersion initially and should not be used on soil that disperses readily.
    • Competition between cheatgrass and two native species after fire: Implications from observations and measurements of root distribution

      Melgoza, G.; Nowak, R. S. (Society for Range Management, 1991-01-01)
      During 1987 and 1988, a study was conducted in northern Nevada to examine root growth of cheatgrass (Bromus tectorum L.) and 2 native species, needle-and-thread grass (Stipa comata Trin. & Rupr.) and rabbitbrush (Chrysothamnus viscidiflorus (Hook.) NW.), after fire. Profile wall maps were used to determine the distribution of roots in the soil profile for the 2 native species. Root morphology differed between the 2 species: needle-and-thread grass had a flabelliform root system, whereas rabbitbrush had a main tap root with 2-4 major lateral roots. Although total root biomass differed between the species, more than half the root biomass was in the top 0.2 m of soil for both needle-and-thread grass and rabbitbrush. Measurements of root length density were used to evaluate the interaction between root systems of cheatgrass and the native species. Root production of plots with only the native species was not significantly different from that of plots with both the native species and cheatgrass for the first 2 years after fire. Furthermore, root production of plots in a recently burned area was also not significantly different from that in an area burned 12 years prior to our study. Thus, root systems of these species rapidly occupied the belowground space and competed for soil resources after fire, and the presence of cheatgrass partially reduced the root systems of the native species.
    • Control of honey mesquite with clopyralid, triclopyr, or clopyralid:triclopyr mixtures

      Bovey, R. W.; Whisenant, S. G. (Society for Range Management, 1991-01-01)
      Greenhouse and field experiments were conducted to evaluate clopyralid formulations and triclopyr ester alone and in mixtures with clopyralid for control of honey mesquite. In the greenhouse, mixtures of the butoxyethyl ester of triclopyr enhanced the activity of the 2-ethylhexyl ester, the monoethanolamine salt and the free acid of clopyralid when applied in 1:1, 1:2 or 1:4 clopyralid:triclopyr mixtures at total rates of 0.07, 0.14, and 0.28 kg se/ha. The activity of triclopyr was not enhanced by addition of clopyralid. In the field, mixtures of the 1-decyl ester of clopyralid + the butoxyethyl ester of triclopyr were usually more effective than either herbicide applied alone. Addition of 0.14 kg/ha of triclopyr to clopyralid applied at 0.28 kg/ha markedly increased canopy reduction and mortality by at least 47% compared to either herbicide applied alone. Basal pours of diesel oil alone at 0.9 L/tree were usually as effective as diesel oil fortified with esters of clopyralid, 2,4,5-T or triclopyr at 4.8 or 9.6 g/L. Basal sprays of diesel oil + esters of clopyralid, 2,4,5-T or triclopyr in concentrations of 4.8 or 9.6 g/L applied at 0.5 L/tree caused high mortality of honey mesquite trees similar to basal pours. Triclopyr or clopyralid at 4.8 g/L were less effective in diesel oil:water carrier (1:4 or 1:3), respectively, than in diesel oil carrier.
    • Cutting frequency and cutting height effects on rough fescue and parry oat grass yields

      Willms, W. D. (Society for Range Management, 1991-01-01)
      A study was made in the Rough Fescue Grasslands of southwestern Alberta to determine the yield response of rough fescue (Festuca scabrella var campestris Rydb.) and Parry oat grass (Danthonia parryi Scribn.) to 5 cutting frequencies and 3 heights over a 1-year period. The same plants were cut either 1, 2, 4, 8, or 16 times over a 16-week period beginning in mid-May, at 16-, 8-, 4-, 2-, or 1-week intervals, respectively, and at heights of either 5, 10, or 15 cm above ground level. Yield response to cutting treatments differed significantly from the flrst to the third treatment year. In the first year, rough fescue and Parry oat grass produced most forage when cut at a height of 5 cm with 1, 2, or 4 cuts. By the third year, rough fescue produced the greatest yields with a single cut after 16 weeks and Parry oat grass produced the greatest yields when cut at 10 or 15 cm at 1-week intervals. The data confirm the high sensitivity of rough fescue to grazing while the plant is growing and suggest that the greatest benefit from the Rough Fescue Grasslands may be derived by grazing in fall or winter. Summer grazing favors Parry oatgrass, which is more tolerant than rough fescue, but forage production on the grassland is reduced.
    • Economic evaluation of spotted knapweed [Centaurea maculosa] control using picloram

      Griffith, D.; Lacey, J. R. (Society for Range Management, 1991-01-01)
      Spotted knapweed is the most serious range weed problem in western Montana. Although picloram is often used to control knapweed, the economic feasibility of the practice has not been evaluated. We developed a model to economically evaluate spotted knapweed control on rangeland. Model functions describing the dynamics of the plant community preceding and following treatment were derived from field observations in western Montana. Economic returns per management unit were calculated for 3 scenarios: (1) no treatment, (2) containment, and (3) eradication of spotted knapweed. After tax costs and benefits of treatments were analyzed for a 20-year period and discounted to the present. An economic loss in current dollars of 2.38/ha was incurred under the no treatment strategy when 25% of the management unit was initiaily infested with spotted knapweed and the weed was spreading to new acres and replacing desirable forage. After-tax present value of added AUMs in the eradication strategy was greater than the after-tax present value of added costs, 3.41/ha and l.99/ha, respectively. As site productivity, value of an AUM, and rate of knapweed spread to new acres increased, economic returns increased relative to treatment costs. In contrast, herbicide treatment became least cost-effective as knapweed utilization by livestock increased. Thus, economic feasibility of spotted knapweed control varied with economic and biologic conditions.
    • Economically optimal private land grazing strategies for the Blue Mountains of eastern Oregon

      Quigley, T. M.; Tanaka, J. A.; Sanderson, H. R.; Tiedemann, A. R. (Society for Range Management, 1991-01-01)
      The Oregon Range Evaluation Project implemented 3 levels of grazing management intensities (strategies) on private land pastures in the Blue Mountains of northeastern Oregon. Prior to implementing each management strategy, a coordinated resource plan was prepared and a benefit-cost analysis on each practice and pasture was performed. The goal was to achieve the largest economic return from grazing for each strategy implemented. Returns above variable costs were used to select the optimal grazing strategy for the ecosystems represented. The commodity production strategy was found to be optimal in all ecosystems over a wide range of interest rates, management costs, and beef prices.
    • Effects of competition on spatial distribution of roots of blue grama

      Coffin, D. P.; Lauenroth, W. K. (Society for Range Management, 1991-01-01)
      The spatial distribution of roots of the perennial grass blue grama [Bouteloua gracilis (H.B.K.) Lag. ex Grifftths] was evaluated under 2 competitive conditions. The radioistope 14C was used to label roots of blue grama plants growing with and without neighboring plants of the same lifeform. The majority of labeled blue grama roots (>75%) were found within 5 cm of the plant and within 10 cm of the soil surface. Labeled roots extended at least 30 cm from the edge of the plant and to depths of at least 90 cm. Root system morphology was insensitive to changes in competitive conditions. Based on our estimates of the depth and breadth of the root system of an average blue grama plant, roots associated with at least 4 other blue grama plants of average size and separated by average distances of 10 cm might occur within the volume of soil associated with roots of this plant. The distribution of total root biomass was not representative of the distribution of labeled roots, even when neighboring grasses were removed.
    • Grazing impacts on litter and soil organic matter in mixed prairie and fescue grassland ecosystems of Alberta

      Naeth, M. A.; Bailey, A. W.; Pluth, D. J.; Chanasyk, D. S.; Hardin, R. T. (Society for Range Management, 1991-01-01)
      Impacts of long-term cattle grazing on litter and soil organic matter were assessed in mixed prairie, parkland fescue, and foothills fescue grasslands of Alberta, Canada. Grazing regimes were of light to very heavy intensities, grazed early, late, and continuously during the growing season. Litter and soil organic matter were sampled in 0.1-m2 quadrats and removed as live vegetation, standing litter, fallen litter, and soil organic matter. Litter and organic matter samples were air dried and sorted by size using sieves and an automatic sieve shaker. Organic carbon content was determined by thermal oxidation. Ground cover was determined using point frames, and heights of standing litter and fallen litter were measured. Heavy intensity and/or early season grazing had greater negative impacts on litter and soil organic matter than did light intensity and/or late season grazing. Under the former regimes there were significant reductions in heights of standing and fallen litter, decreases in live vegetative cover and organic matter mass, and increases in bare ground. More large particle-sized organic matter, particularly standing litter, occurred in controls than in grazed treatments since it would not be removed or trampled by grazing animals. More medium and small particle-sized organic matter occurred in grazed treatments than in ungrazed controls since vegetation likely decomposed more rapidly when it was trampled and broken down as animals grazed.
    • Influences of temperature and water stress on germination of plains rough fescue

      Romo, J. T.; Grilz, P. L.; Bubar, C. J.; Young, J. A. (Society for Range Management, 1991-01-01)
      Germination of 12 collections of pIains rough fescue (Festuca altaica Trin. subsp. hallii (Vasey) Harms) from Saskatchewan was evaluated in 55 constant and alternating temperature regimes ranging from 0 to 44 C. Combined influences of temperature and water stress on germination were studied by incubating seeds in a gradient of osmotic potentials at constant temperatures of 5, 10, 15, 20, and 250 degrees C and under regimes where temperatures were either increased from 10 to 25 degrees C or decreased from 25 to 100 degrees C. Seeds germinated in 80 to 87% of the 55 temperature regimes tested with maximum total germination between populations ranging from 34 to 100%. Germination was highest most often at constant temperatures of 15 and 20 degrees C, but seeds germinated over a wide range of temperatures. Germination rate and total germination responded to the interacting effects of temperature and osmotic potential. Under constant temperatures, 71 to 88% of the variation in germination was accounted for by osmotic potential. Seeds germinated fastest, in the highest numbers, and over the broadest range of osmotic potentials at 10 to 20 degrees C. Germination was higher and more rapid over the range of osmotic potentials when temperatures increased from 10 to 250 degrees C than when they declined from 25 to 10 degrees C. Osmotic potential accounted for 65 to 74% of the variation in germination. The plastic response of germination to temperature suggested that while this factor does not limit regeneration of plains rough fescue from seed, germination is severely restricted by declining osmotic potentials. These moisture limitations reflected adaptations that preclude germination under conditions of transient moisture or low moisture availability. Plains rough fescue should be pbted in the spring when temperatures are rising and soil moisture is highest.
    • Late season control of honey mesquite with clopyralid

      Jacoby, P. W.; Ansley, R. J.; Meadors, C. H. (Society for Range Management, 1991-01-01)
      Herbicides were applied aerially to honey mesquite (Prosopis glandulosa Torr.) in the Rolling Plains and Edwards Plateau land resource areas of Texas to evaluate efficacy during late season applications. Although other herbicides gave higher levels of above ground mortality, clopyralid caused higher whole plant mortality throughout the growing season than 2,4,5-T + picloram, both of which were ineffective when applied in September. Mixtures of clopyralid + picloram also were less effective when applied during later periods in the growing season, suggestiong picloram added little or even reduced the efficacy of clopyralid for late season control of honey mesquite. Triclopyr alone or in combination with picloram was ineffective in controlling honey mesquite in the fall. Clopyralid in the fall was most effective when applied at rates of 0.56 kg ha-1 or more. Dosage response of honey mesquite in late season applications (late August to October) was practically identical to that found for applications made in June and July, which indicates that clopyralid provides constant levels of mortality throughout the growing season. This research supports the practice of extending the season of applications with clopyralid into the fall. Applications in the fall might allow more rangeland to be treated for honey mesquite reduction and also reduce risks associated with drift damage to crops during their most susceptible periods of growth in early to mid-summer.
    • Response of tap- and creeping-rooted alfalfas to defoliation patterns

      Gdara, A. O.; Hart, R. H.; Dean, J. G. (Society for Range Management, 1991-01-01)
      Under grazing, creeping-rooted alfalfa (Medicago sativa L.) cultivars have been reported to be more productive and have higher survival than tap-rooted cultivars. To determine if differences in persistence could be related to response to defoliation patterns, we clipped 3 tap- and 3 creeping-rooted alfalfa cultivars. Different fractions of the total number of stems were clipped to different stubble heights every 21 days. Both tap- and creeping- rooted cultivars responded similarly to defoliation. Maximum forage production was obtained when one-third of the stems on a plant were cut back to 5 cm above the ground at each harvest. The lowest forage production was obtained when all stems on a plant were cut back to 5 cm. The most lenient defoliation (one-third of the height of one-third of the stems removed at each harvest) maximized total herbage production (forage plus stubble) but only 32% of the herbage was harvested as forage, leaving 68% as unharvested stubble. Severe defoliation every 21 days decreased the concentration of total nonstructural carbohydrate in the roots and reduced total root biomass. Thirteen alfalfa cultivars responded similarly to grazing when seeded in dense stands. The greater persistence of creeping-rooted alfalfa cultivars under grazing does not appear to be a result of greater intrinsic productivity or more rapid recovery from defoliation. The lateral spread of individual creeping-rooted plants in open stands may increase the probability that some stems will escape defoliation at each grazing; these stems then contribute to rapid recovery from grazing and to plant survival.
    • Seedstalk production of mountain big sagebrush enhanced through short-term protection from heavy browsing

      Wagstaff, F. J.; Welch, B. L. (Society for Range Management, 1991-01-01)
      Mountain big sagebrush (Artemisia tridentata ssp. vaseyana Nutt.) is an important browse species on many key mule deer winter ranges in the western United States. Big sagebrush on many of those ranges is declining due to the lack of recruitment. Plants subjected to heavy 0 8% use) browsing produce 50 to 93% fewer seedstalks than those not subject to such use. The objectives of this study were to determine: (1) whether protection from browsing for 1 winter would increase the number of seedstalks the following fall; (2) if protection increased length of seedstalk; (3) if there is a relationship between seedstalk length and number of seeds per seedstalk; and (4) if increasing seed production increased seedling establishment. Fifty-eight plots containing 344 plants at 4 sites in north-central Utah were established. At each plot, plants were randomly assigned to be either protected or browsed. The protected plants produced significantly (P<0.05) more seedstalks than those browsed during the previous winter. Length of seedstalks on a given plant and among plants showed considerable variation, and the data indicated no clear differences between average seedstalk length on browsed and protected plants. Seed per unit length of seedstalk was also highly variable. No seedlings were found during 7 years of observations of the original plot or in 4 years for the 57 plots established in 1986, regardless of the numbers of seedstalks on a plant. Seed production does not appear to be a limiting factor in seedling establishment for the study populations.
    • Some effects of precipitation patterns on mesa dropseed phenology

      Gibbens, R. P. (Society for Range Management, 1991-01-01)
      Phenology of mesa dropseed [Sporobolus flexuosus (Thurb.) Rydb.] was studied from 1979 to 1987 on the Jornada Experimental Range in southern New Mexico. Growing season (March through November) precipitation ranged from 99 to 308 mm during the 8-year period. Foliage height and number of leaves were recorded weekly for individually marked culms on 20 plants. New culms usually appeared during the first week in March and green leaf tissue often persisted until the end of November. Correlation analyses of accumulated weekly height increments and accumulated weekly precipitation showed that growth was highly dependent upon rainfall (r = 0.81 to 0.97). Leaf formation was also correlated with rainfall (r = 0.79 to 0.98). Even in relatively wet years tbere were 1 or 2 periods of no growth. In drier years, no growth periods totaled as much as 87 days. Periods of rapid growth occurred only after rainfall events > 13 mm. The first exsertion of seed heads occurred as early as the last week of July and as iate as the second week of October. The temporal plasticity of mesa dropseed phenology indicates that it is well adapted to the arid environment.
    • Substrate relations for rillscale [Atriplex suckleyi] on bentonite mine spoil

      Voorhees, M. E.; Uresk, D. W.; Trlica, M. J. (Society for Range Management, 1991-01-01)
      Rillscale (Atriplex suckleyi), the dominant native invader of bentonite mine spoil in northern Wyoming, is apparently uniquely adapted to this extremely harsh plant growth substrate. The objective of this study was to determine which chemical properties of spoil influence growth of rillscale. Plant production, foliar and spoil chemistry on spoils were treated as a factorial arrangement of treatments, each of 3 spoil amendments (gypsum, fertilizer, sawdust). Regression analyses with analysis of covariance and factorial analysis of variance model were used to control for effects of amendments on plant production. Calcium and nitrogen were growth-limiting nutrients for this plant. The species was very sensitive to an increase in the level of spoil molybdenum and in the ratio of copper to molybdenum, but was very tolerant of high levels of soluble sodium. Rillscale acted as a molybdenum accumulator.
    • Summer habitat use and activity patterns of domestic sheep on coniferous forest range in southern Norway

      Warren, J. T.; Mysterud, I. (Society for Range Management, 1991-01-01)
      Eight domestic sheep (Ovis aries L.) ewes were fitted with radio collars and tracked during the 1985 grazing season in Trysll, Hedmark County, southern Norway. The ewes were relocated 761 times between 11 June until 13 September. All relocations were used to describe activity patterns, and 565 were plotted and used to estimate habitat use. Range use was initially concentrated on and about areas previously referenced by man (e.g., abandoned homesteads, old fields) and on adjacent stands of rich spruce/fern (Picea abies (L) Karsten)/(Dryopteris spp.) forest. This preference was displayed especially during the day; poorer forest types were used more in the evening and at night. As the season progressed, use of the meadow/old-field habitat type declined in favor of the forest types. Activity peaks were at mid-morning and late evening. Animals camped in groups at midday and at night, always further upslope at night than during the day. Sheep were less active in cold, wet weather. Habitat selection and activity patterns observed in this study were similar to those of both wild and domestic sheep studied elsewhere.
    • Technical Notes: A technique to determine seed location in relation to seedbed preparation treatments

      Winkel, V. K.; Roundy, B. A. (Society for Range Management, 1991-01-01)
      Distribution of seeds buried by different seedbed preparation techniques can be determined by seeding small plots at a high rate, wetting the soil and extracting soil cores in plastic vials. Seeds can be located with a dissecting scope when cores are split in half. Although the technique may slightly underestimate the percentage of small buried seeds like those of Lehmann lovegrass (Eragrostis lehmanniana Nees), it permits the analysis of large numbers of samples.
    • Water holding capacity of litter and soil organic matter in mixed prairie and fescue grassland ecosystems of Alberta

      Naeth, M. A.; Bailey, A. W.; Chanasyk, D. S.; Pluth, D. J. (Society for Range Management, 1991-01-01)
      Litter and organic matter accumulations can reduce soil water through interception of precipitation and subsequent evaporation of absorbed water. Interception varies with mass and water holding capacity (WHC) of litter and organic matter, and is highest from small precipitation events. WHC varies with vegetation type, which is affected by grazing regime. Thus long-term grazing could affect WHC of litter and organic matter and would be important in the hydrologic assessment of rangelands subjected to many small precipitation events throughout the growing season. The study was conducted in mixed prairie, parkland fescue, and foothills fescue grasslands in Alberta, Canada. Grazing regimes were of light to very heavy intensities, grazed early, late, and continuously during the growing season. Litter and organic matter were sorted by sieving into various sized categories. Litter-soil cores were also evaluated. WHC of litter and organic matter was lower in mixed prairie than in fescue grasslands. WHC increased with increazed particle size, being higher for roots and standing and fallen litter than for organic matter. WHC of large particle-sized material decreased with heavy intensity and/or early season grazing. WHC was affected more by intensity than season of grazing. Grazing affected WHC through species composition changes, since species have different WHC, and through trampling which affected particle size. It was concluded that litter and organic matter WHC were important in rangeland hydrologic assessments.