• A comparison of frontal, continuous, and rotation grazing systems

      Volesky, J. D.; O'Farrell, F. De Achaval; Ellis, W. C.; Kothmann, M. M.; Horn, F. P.; Phillips, W. A.; Coleman, S. W. (Society for Range Management, 1994-05-01)
      Two 2-year trials were conducted to evaluate and compare frontal, continuous, and 2-paddock rotation grazing systems on 'Plains' Old World bluestem (Bothriochloa ischaemum (L.) Keng.). Frontal grazing allows livestock a continuous opportunity to graze fresh forage via a livestock-pushed, sliding fence which allocates and controls grazing within a pasture. Trial 1 treatments included frontal grazing at a very high stocking density of 13.3 head ha-1 and continuous grazing at 4 stocking densities described as low, moderate, high, and very high. The mechanical design and components of our frontal grazing system were quite adequate in terms of the system's operation and interaction with the livestock herd. Significant (P < 0.05) linear relationships were found for regressions of daily gain on stocking rate and grazing pressure index, and for gain ha-1 on stocking rate and grazing pressure index. Year effects were evident in all regressions. Trial 2 treatments included frontal, continuous, and rotation grazing systems initially stocked at 6.7 head ha-1. Mid-season reductions in stocking density were made in continuous and rotation grazing to ensure that these treatments would have adequate forage to continue until frontal grazing completed its second cycle and to achieve an end-of-season standing crop which was similar in all 3 treatments. Season-long daily gains under frontal grazing were not significantly different compared to continuous grazing (P > 0.05); however, they were less than those under rotation grazing (P < 0.05). Frontal grazing provided about 100 more steer-days per hectare of grazing than either continuous or rotation grazing. However, steer production was not significantly different among treatments and averaged 296 kg ha-1 (P > 0.05).
    • Diet selection and utilization by llama and sheep in a high altitude-arid rangeland of Bolivia

      Genin, D.; Villca, Z.; Abasto, P. (Society for Range Management, 1994-05-01)
      Botanical composition of llamas and sheep diets were quantified monthly during 1 year in the arid highlands of Bolivia to identify competition between these species for forage resources. Results indicated higher proportions of coarse bunchgrasses in llamas diets (48 to 75%) than in sheep (37 to 68%), while sheep consumed more soft herbs and grasses than llamas (25 to 45%, and 8 to 25%, respectively). Llamas had higher (P < 0.05) digestion coefficients than sheep for organic matter, dry matter, crude protein, and fiber fractions of the principle bunchgrass paja brava (Festuca orthophylla) during the vegetative phenological stage. Shrubs represented less than 20% of the diet components in both llamas and sheep. A canonical discriminant analysis showed that there was not a strong dietary overlap between these species, and suggested that mixed herds could allow a better utilization of the overall available forage.
    • Drying and storage effects on germination of primed grass seeds

      Hardegree, S. P. (Society for Range Management, 1994-05-01)
      Cheatgrass (Bromus tectorum L.) has become the dominant species over large areas of rangeland in the Great Basin region of the western United States. Rapid germination at low temperature may contribute to the competitive success of cheatgrass in areas formerly dominated by native sagebrush and bunchgrass species. The objectives of this study were to determine whether seed priming could be used to stimulate low-temperature germination rate of native bunchgrass seeds and whether any priming effect was retained after drying and storage. Matric-priming was used to enhance germination rate response of 7 Great Basin native perennial grasses: thickspike wheatgrass [Agropyron dasystachyum (Hook.) Scribn.], bluebunch wheatgrass [Pseudoroegneria spicata (Pursh) Love], canby bluegrass (Poa canbyi Scribn.), sandberg bluegrass (Poa sandbergii Vasey.), bottlebrush squirreltail [Sitanion hystrix (Nutt.) J.G. Smith], sheep fescue (Festuca ovina L.), and basin wildrye [Leymus cinereus (Scribn. and Merr.) A. Love]. Priming enhanced germination rate of these species by 4 to 8 days at 10 degrees C. All species except canby bluegrass and basin wildrye could be induced to germinate as quickly as cheatgrass if they were not air-dried after priming. All species except canby bluegrass retained significant germination enhancement after 11 weeks of storage but only bluebunch wheatgrass maintained a germination rate comparable to cheatgrass when seeds were dried for storage.
    • Harvest date and fertilizer effects on native and interseeded wetland meadows

      Reece, P. E.; Nichols, J. T.; Brummer, J. E.; Engel, R. K.; Eskridge, K. M. (Society for Range Management, 1994-05-01)
      Studies of harvest date by fertilizer interactions on hay meadows are rare and none have been published for prairie meadows. Our objective was to evaluate the effects of initial harvest date (15 June, 15 July, and 15 August) and spring-applied N (0, 45, 90, and 135 kg ha-1) on first cutting and regrowth dry matter yield and forage quality from native and interseeded wetland meadow sites. Regrowth was harvested on all plots in late September. 'Garrison' creeping foxtail (Alopecurus arundinaceus Poir.) was interseeded on plots 4 years prior to application of treatments. Native vegetation was dominated by sedges (Carex spp.). Interseeded plots were dominated by Garrison creeping foxtail. Yield and quality on different dates and response to N were similar for vegetation types despite differences in duration of spring flooding between years. Harvest date by fertilizer interactions occurred for first cutting yield and crude protein concentration. Yield response to applied N ranged from 8.5 to 31.2 kg ha-1 kg-1 N. Fertilizer had no effect on digestibility and increased crude protein concentration only in herbage harvested on 15 June. Within levels of N, first cutting yield was about 60% of peak standing crop on 15 June and 90% on 15 July compared with 15 August. Greater plant growth rates and response to N after prolonged spring flooding compensated for initial differences between years by 15 July. Regrowth dry matter yield was not affected by spring-applied N and increased by about 43 kg ha-1 day-1 after initial harvest in both years. Sedge-dominated, prairie meadows are productive and provide predictable forage and wildlife habitat management alternatives.
    • Indications of associative nitrogen fixation in eastern gamagrass

      Brejda, J. J.; Kremer, R. J.; Brown, J. R. (Society for Range Management, 1994-05-01)
      Associative nitrogen-fixation is one mechanism by which plants can meet a portion of their nitrogen (N) needs in N deficient environments. Eastern gamagrass [Tripsacum dactyloides (L.) L.] grows under conditions conducive for associative N-fixation. Our objective was to evaluate eastern gamagrass roots for nitrogenase activity and associated N-fixing bacteria, and compare its nitrogenase activity to switchgrass (Panicum virgatum L.). Soil and root samples were collected from unfertilized stands of "PMK-24" eastern gamagrass at 3 locations in northern Missouri and nitrogenase activity measured using the acetylene reduction method. Eastern gamagrass roots supported greater nitrogenase activity when colonized by indigenous bacteria, compared to roots inoculated with Klebsiella pneumoniae or surface sterilized. Eastern gamagrass roots colonized by indigenous bacteria had 17-46 fold greater nitrogenase activity than switchgrass roots. Bacterial composition on eastern gamagrass roots was dominated by fluorescent pseudomonads and Pseudomonas cepacia, with lower populations of other bacteria. Bacterial composition from incubation tubes showing nitrogenase activity was similar to that found on the roots, except that the diazotrophic bacterium Azospirillum braziliense was isolated from 1 of 3 sites. The potential for associative N-fixation with eastern gamagrass warrants further study and in situ measurement to quantify rates of N fixation.
    • Little bluestem tiller defoliation patterns under continuous and rotational grazing

      Derner, J. D.; Gillen, R. L.; McCollum, F. T.; Tate, K. W. (Society for Range Management, 1994-05-01)
      Defoliation patterns of little bluestem [Schizachyrium scoparium (Michx.) Nash] on tallgrass prairie were compared using continuous and rotational grazing systems on six 24-ha pastures for each system over a range of stocking rates (0.28 to 0.49 AU ha-1) in 1991 and 1992. We tested the generalization that rotational grazing provides greater managerial control over the frequency, intensity, and uniformity of tiller defoliation compared to continuous grazing. Rotational system pastures were subdivided into 8 paddocks with 4 grazing cycles (3-7 day graze periods) per grazing season. Tillers were sampled biweekly in continuous system pastures and at the beginning, midpoint, and end of each grazing period in rotational system pastures. Multiple regression prediction equations were developed for grazed height, number of defoliation events in a grazing season, percent of tillers defoliated per sampling period (of continuous system) and grazing cycle (for rotation system), and number of defoliation events within a grazing cycle (rotational system). Grazed height decreased as stocking rate increased, but was not influenced by grazing system. The number of cumulative defoliation events per tiller increased with increasing stocking rate over the grazing season. Under similar stocking rates, a higher percentage of tillers were defoliated during the grazing season in the continuous than in the rotational grazing system. Within both grazing systems, percentage of tillers defoliated increased with increasing stocking rates. The percentage of tillers defoliated biweekly in continuous system pastures was similar over the grazing season; the percentage of tillers defoliated per cycle increased as grazing periods lengthened in rotational system pastures. A large number of tillers were defoliated during the second half of each grazing period. Less than 10% of tillers were regrazed within a grazing cycle, even at the highest stocking rate and longest grazing period. Rotational grazing provided greater managerial control over the frequency and uniformity of tiller defoliation; intensity of tiller defoliation was similar between the 2 grazing systems. We hypothesize higher range condition will be maintained over the long-term in rotational system pastures as little bluestem will remain more competitive and productive resulting from fewer defoliation events throughout the grazing season.
    • Nutrient quality of bluebunch wheatgrass regrowth on elk winter range in relation to defoliation

      Westenskow-Wall, K. J.; Krueger, W. C.; Bryant, L. D.; Thomas, D. R. (Society for Range Management, 1994-05-01)
      Effects of defoliating bluebunch wheatgrass (Agropyron spicatum [Pursh] Scribn. & Smith) to increase the quality of regrowth available on Rocky Mountain elk (Cervus elaphus nelsoni Bailey) winter range were studied from 1988 through 1990. Percent calcium, phosphorus, in vitro dry matter digestibility (IVDMD), and available forage (kg/ha DM) of regrowth present on control, spring-defoliated, and fall-defoliated plots were determined in November of 1988 and 1989, and April of 1989 and 1990. Spring conditioning did not affect the percentage of calcium and phosphorus, or available forage compared to the current year's growth in either November or April. Fall conditioning increased digestibility and increased the phosphorus concentration, but decreased available forage compared to the control and spring-conditioned forage in November. Fall conditioning may create a deficit of forage if regrowth is not achieved. Additional research is needed on defoliation during the early phenological time-period of bluebunch wheatgrass to improve the forage quality of elk winter ranges.
    • Plant responses to gypsum amendment of sodic bentonite mine spoil

      Schuman, G. E.; Depuit, E. J.; Roadifer, K. M. (Society for Range Management, 1994-05-01)
      Abandoned bentonite mine spoils are extremely difficult to revegetate because of their high clay content, salinity, sodicity, low permeability, and the semiarid climate of the area where bentonite mining occurs. Recent research has led to the development of technology utilizing sawmill wastes (chips, bark, and sawdust) to enable the successful revegetation of these lands. The use of wood residue amendments increased water infiltration, leaching of soluble salts, and vegetation establishment; however, sodicity continued to be a problem and threatened to destroy the established vegetation. Surface application of gypsum was evaluated to determine its effectiveness in ameliorating the spoil sodicity and its effect on plant growth. In a 3-year field study, surficial gypsum amendment resulted in significant increases in perennial grass biomass (150%) and canopy cover (140%). These changes were not evident until the second or third year after gypsum amendment. Annual forb biomass did not respond to gypsum amendment; however, canopy cover did exhibit a significant increase in the second year at lower wood residue amendment rates. This research demonstrates that surface applied gypsum can be effective in ameliorating bentonite spoil sodicity when applied to established plant communities.
    • Potential forage value of some eastern Canadian sedges (Cyperaceae: Carex)

      Catling, P. M.; McElroy, A. R.; Spicer, K. W. (Society for Range Management, 1994-05-01)
      The relationship between forage value and various factors, including sectional classification, species, moisture, light, and date and year of collection, was explored with analysis of variance in 317 collections representing 77 species of Carex. Most of the sedges analyzed would exceed the energy required for livestock maintenance. There was great variability within and between species and sections in forage values defined in terms of crude protein, acid-pepsin digestibility, and acid detergent fibre content. Some species, such as C. praegracilis, have crude protein levels of about 15%, acid-pepsin digestibility exceeding 33%, and acid detergent fibre less than 33%, making them equivalent to a good quality grass hay. It was not possible to make generalizations about correlation with light and moisture, but rhizomatous species had higher acid-pepsin digestibility (P < 0.10) and lower acid detergent fibre (P < 0.01) than caespitose species. Forage quality was highest in the beginning of the season. Crude protein decreased 0.04 to 0.09% units/day and acid-pepsin digestibility declined 0.06 to 0.11 units/day. In 2 of the 3 years, acid detergent fibre increased significantly (P < 0.01) over time. The classification system appears to be useful in identifying species and species groups with the greatest forage potential. Some sedge species with relatively low forage value are nevertheless utilized by cattle. Natural habitats and native forages, such as sedges, may be far more valuable than is currently realized, and the trend toward increasingly efficient landscape use will require a better understanding of their value and management.
    • Predicting big sagebrush winter forage by subspecies and browse form class

      Wambolt, C. L.; Creamer, W. H.; Rossi, R. J. (Society for Range Management, 1994-05-01)
      Improved regression models were developed to predict winter forage production from big sagebrush (Artemisia tridentata Nutt.) through consideration of the subspecies variation among mountain big sagebrush (A.t. ssp. vaseyana [Rydb.] Beetle), Wyoming big sagebrush (A.t. ssp. wyomingensis Beetle and Young), and basin big sagebrush (A.t. ssp. tridentata). Changes in shrub morphology from browsing were also accommodated in our models. Colinearities among some variables used in previous studies were found and avoided in our models. Models used easily measured objective variables of which major axis and average cover of shrubs were most useful. Multivariable models without colinearities were evaluated on the basis of their R2a values which increased by an average of 10% to near 0.90, with taxa and browse form class included, compared to a model ignoring these differences.
    • Sites, mowing, 2,4-D, and seasons affect bitter-brush twig morphology

      Kituku, V. M.; Powell, J.; Olson, R. A. (Society for Range Management, 1994-05-01)
      Effects of site factors, mowing, 2,4-D, and seasons on antelope bitterbrush (Purshia tridentata Pursh.) twig length, basal and tip diameters, and weight were evaluated in southcentral Wyoming. Linear regression coefficients for twig length regressed on basal diameter were greater on productive sites than on less productive sites, greater on mowed areas than on sprayed or untreated areas, and greater in late fall because of leaves than in late winter. Twig elongation continued after data collection in early November. Twig length was more variable and more sensitive to different environmental conditions than twig basal diameter, tip diameter, or weight. Twig length accounted for 80-86% of the variation in twig weight. Sites, shrub management practices, and seasons do affect bitterbrush twig morphology, but habitat managers can use twig length-diameter-weight relations in this vegetation type to estimate utilization if the sampling is stratified along environmental gradients.
    • Sixty-one years of secondary succession on rangelands of the Wyoming high plains

      Samuel, M. J.; Hart, R. H. (Society for Range Management, 1994-05-01)
      The slow and uncertain rate of recovery of plant communities after severe disturbance is a major problem on rangelands. Earlier studies sketched the outline of secondary succession on mixed-grass prairie, but were based on 1 or 2 years of observation on different areas disturbed at different times in the past, or several years of observation of a single area. To provide a more complete picture of succession over decades, we began observations in 1977 on 4 areas disturbed from 1 to 51 years previously, and on undisturbed areas of the same 2 soil types with and without grazing. Observations continued for 11 years. Secondary succession proceeded through the usual stages: annual forbs, perennial forbs and annual grasses, short-lived perennial grasses, and long-lived grasses. Western wheatgrass [Pascopyrum smithii (Rydb.) A Love] was an exception because it appeared much earlier and in much greater abundance than other long-lived perennial grasses. Blue grama [Bouteloua gracilis (H.B.K.) Lag ex. Steud.) may be another exception; total recovery of this grass may require centuries. Time of appearance in succession seemed to be related to availability of propagules and ease of establishment; persistence of species was related to competitive ability. Abundance of many species fluctuated widely from year to year, but fluctuations did not appear to be related to precipitation. After 61 years, secondary succession had not returned plant communities to the climax state.
    • Technical Note: Inexpensive rain gauges constructed from recyclable 2-liter plastic soft drink bottles

      Wrage, K. J.; Gartner, F. R.; Butler, J. L. (Society for Range Management, 1994-05-01)
      A large number of inexpensive rain gauges were required for a study currently being conducted in the Black Hills of South Dakota. A gauge utilizing discarded 2-liter plastic soft drink bottles was designed and constructed at very low cost. Assembly took less than 5 minutes per gauge and required minimal equipment. The gauges have been in use for 1 growing season and have provided accurate, reliable data.
    • Technical Note: Mechanical harvesting of plains pricklypear for control and feeding

      Mueller, D. M.; Shoop, M. C.; Laycock, W. A. (Society for Range Management, 1994-05-01)
      Plains pricklypear cactus (Opuntia polyacantha L.) is abundant on the Central Great Plains with dry matter yields from 1,500 to 2,000 kg/ha. Cactus spines prevent cattle from grazing as much as 50% of the herbage around the plant. Pricklypear pads are quite palatable once spines have been removed. The possibility of simultaneously controlling and feeding plains pricklypear led to development of machinery for harvesting cactus. The harvesting machine is a side-delivery rake modified to uproot and windrow pricklypear which is later despined and fed to cattle. Machine harvesting was compared to hand harvesting on both a sandy loam and a clay loam site. There was no significant difference in cactus removal between hand and machine harvested plots or significant damage to desirable forage species. Pricklypear phytomass removal by the harvester averaged 89% and 88% on the sandy and clay loam sites, respectively. This provided an average of 1,166 kg/ha cactus as potential feed and increased availability of desirable forage species.
    • Tiller defoliation patterns under frontal, continuous, and rotation grazing

      Volesky, J. D. (Society for Range Management, 1994-05-01)
      An investigation was conducted to characterize the intensity and frequency of tiller defoliation in 'Plains' Old World bluestem (Bothriochloa ischaemum (L.) Keng) under frontal, continuous, and 2-paddock rotation grazing systems. Frontal grazing allows cattle a continuous opportunity to graze fresh forage via a livestock-pushed sliding fence that allocates and controls grazing within a pasture. Nearly 100% of frontal grazing tillers were defoliated at least once during a 3-hour period as the frontal fence was advanced over the transect ares. The initial defoliation intensity of tillers under frontal grazing was also significantly higher and remaining tiller height less than that of tillers under rotation or continuous grazing (P < 0.05). Tillers under frontal grazing were defoliated at a faster rate compared to rotation or continuous grazing, but cattle had access to them for only 6 to 8 days of the entire grazing season. Season-long defoliation frequency was estimated to be 2.4, 4.6, and 4.7 times for frontal, continuous, and rotation grazing, respectively. Tillers that originated from the perimeter of a tussock were initially taller than those arising from the center (P < 0.05); however, frequency and intensity of defoliation was similar for both tiller locations. Significant relationships were also described between defoliation frequency and stocking rate and between defoliation frequency and herbage allowance. Defoliation frequency increased linearly as stocking rate increased; and conversely, defoliation frequency decreased quadratically as herbage allowance increased. Data from this study suggest that the pattern of tiller defoliation under frontal grazing enhanced forage production which allowed the maintenance of higher stocking rates.
    • Vegetation characteristics influencing site selection by male white-tailed deer in Texas

      Pollock, M. T.; Whittaker, D. G.; Demarais, S.; Zaiglin, R. E. (Society for Range Management, 1994-05-01)
      We studied the effects of vegetation characteristics in southern Texas on site selection by mature, male white-tailed deer (Odocoileus virginianus Raf.). Thirteen, radio-collared animals were monitored during winter, spring, summer, and fall of 1986-87 and 1987-88 to determine area-usage patterns within each animal's respective seasonal home range. After each season, structural vegetation attributes were measured with transect-oriented data collection techniques inside the most heavily used and unused areas of each animal's home range. Comparisons were made between these areas to determine whether site selection by deer was in response to differing vegetation characteristics. In general, the most heavily used areas possessed a greater amount of woody canopy cover (greater than or equal to 85%), woody species richness (18-20), and horizontal screening cover than areas with no use. In contrast, herbaceous densities did not differ between the most heavily used and unused areas. Consequently, habitat management manipulations conducted specifically for mature male white-tailed deer in southern Texas, should include provisions for creation or maintenance of sites possessing dense woody canopy cover, a high number of woody species and dense horizontal screening cover.