• Cattle as a dispersal agent of Acaena elongata (Rosaceae) in the cordillera of Merida, Venezuela

      Molinillo, M. F.; Brener, A. G. F. (Society for Range Management, 1993-11-01)
      In the tropical Andean environments little is known about the relationship between weed dispersal and disturbances caused by cattle. We propose that abundance and dispersal of the Venezuelan Andean weed Acaena (Acaena elongata L.) is associated with the widespread grazing habits of cattle. We studied Acaena presence in areas with different cattle movements and grazing intensities. Acaena density increased with cattle trail density (r2 = .98, P < .001). Infestation patterns suggested dispersal by cattle along trails. Areas with greater cattle movement (0.34 trails/m) possessed the greatest density and highest number of Acaena plants (P < .001). This weed has morphological and phenological features adapted to cattle dispersal. Fruits mature during the season when cattle are less selective and travel the greatest distances.
    • Effects of cattle ingestion on viability and germination rate of calden (Prosopis caldenia) seeds

      Peinetti, R.; Pereyra, M.; Kin, A.; Sosa, A. (Society for Range Management, 1993-11-01)
      Caldén (Prosopis caldenia Burkart) is the dominant tree of the xerophytic open forest in the semiarid pampa of Argentina. caldén has gradually increased its distribution throughout the region during the past century as a result of livestock grazing in the pampa forest. Caldén has an indehiscent legume fruit that is consumed by livestock during the February-April fruit shedding period (FSP). Both free seeds and pod segments (1 seed inside the endocarp) can be found in cattle dung. Free seeds and pod segments coming from fruits (uningested) and dung (excreted) were collected during the fruit shedding period on 22 February (D1), 7 March (D2) and 27 March (D3) to compare viability and germination rate. Viabilities of uningested free seeds and pod segments averaged 95% and 65%, respectively, and were unaffected (P less than or equal to 0.01) by date of collection. Excreted free seed from D1 was 37% viable, which was lower (P less than or equal to 0.01) than the 72% viable for D2 and D3. Excreted pod segments averaged only 10% viable seeds. Ingestion increased (P less than or equal to 0.01) germination rate of free seed for D1 and D3. However, excreted seed displayed a range of delayed germination response. This diversity would increase the probability of seed germination for a variety of environmental and site conditions.
    • Effects of media N content and rhizobial strain on N2 fixation and partitioning in Leucaena seedlings

      Dovel, R. L.; Vietor, D. M.; Weaver, R. W. (Society for Range Management, 1993-11-01)
      Research was conducted to examine the effect of Rhizobial race and N fertilization on N2 fixation and N partitioning in seedlings of the genus Leucaena. Seedlings of Leucaena leucocephala (Lam) Dewit variety K-8 and L. retusa Gray variety Yellow Puff were grown in slender tubes filled with fritted clay and watered with nutrient solutions containing 0, 2, or 8 mM nitrate N labeled with 0.1% N15. The seedlings were inoculated with Rhizobia loti race 94A3 or R. logi race 9408. After 12 weeks the plants were harvested and the effects of N fertilization and Rhizobial race on nodulation N2 fixation, and N partitioning were examined. Using the N15-dilution method total N fixed by dinitrogen fixation was determined as well as distribution of fixed versus fertilizer N within the plant. Both Rhizobial races infected both Leucaena species resulting in an effective symbiosis. However, the 2 Leucaena species responded quite differently to N fertilization. The addition of 2 mM N to the nutrient solution effectively eliminated nodulation in L. retusa yet increased both nodulation and N2 fixation in L. leucocephala. The 8 mM N rate eliminated nodulation in both species. Due to the elimination of nodulation and N2 fixation by N fertilization in L. retusa, the effect of N fertilization on partitioning of fixed N was only examined in L. leucocephala. Increasing the N content of the nutrient solution increased the proportion of total N in the shoot and reduced the proportion in nodules. A larger proportion of the fixed N was retained in the root and nodules than fertilizer N. Although the 2 mM N treatment increased the amount of N2 fixed in L. leucocephala compared to the 0 mM treatment, the proportion of fixed N2 was reduced to less than one third of the total N in the plant.
    • Alternative grazing fee formula impacts on representative public land ranches

      Anderson, D. P.; Richardson, J. W.; Knutson, R. D.; Namken, J. C.; Harris, T. R.; Champney, W. O.; MacDiarmid, T. R.; Marshall, A. B. (Society for Range Management, 1993-11-01)
      The Farm Level Income Tax and Policy Simulation Model (FLIPSIM) was used to evaluate and quantify the impacts of alternative grazing fee formulas, discussed in the 1986 Grazing Review and Evaluation and its recent update. Economic viability (level of income and risk) was estimated for 4 representative ranches that lease public range lands in the western United States. Average annual net cash income is projected to be positive over the 1992-97 planning horizon although income is projected to decline for the first 4 years as cattle prices weaken. Average annual net cash income under the alternative grazing fee formulas falls by as much as 37% relative to the current Public Rangelands Improvement Act formula for all of the ranches studied. Real net worth of each ranch declines as much as 22% over the study period under the highest alternative grazing fee.
    • Botanical composition and seasonal trends of cattle diets in central Argentina

      Bóo, R. M.; Lindstrom, L. I.; Elía, O. R.; Mayor, M. D. (Society for Range Management, 1993-11-01)
      About 40,000 km2 of the caldénal in central semiarid Argentina are rangelands where the most important economic activity is cow-calf operations. Some information on forage species, mainly regarding taxonomy, ecophysiology, and nutritive value, is available, but detailed studies on composition of free-ranging cattle diets are lacking. The objective of this work was to study the botanical composition and seasonal trends of cattle diets in the southern caldénal. Diets were studied through microscopic analysis of cattle feces collected monthly in a typical plant community during a 12-month period. Grasses were the bulk of the diets, except in November when more than 50% of the diet was Medicago minima (L.) Grufberg. Highest consumption among the grasses was of Piptochaetium napostaense (Speg.) Hack., one of the dominants in the grass layer. High consumption of Pappophorum mucronulatum Nees, one of the few warm-season grasses in the region, was found during the summer. Caldén (Prosopis caldenia Burk.) pods, consumed in late summer and fall, were the only woody fragments found in appreciable amounts. Classification and ordination techniques were used to analyze seasonal trends. In spite of a relatively high homogeneity in the diets, 2 well-defined seasonal trends were detected, one in the fall-winter period and another in the spring. Cattle diet diversity was minimum during the coldest months of the year.
    • Early season utilization of mountain meadow riparian pastures

      Clary, W. P.; Booth, G. D. (Society for Range Management, 1993-11-01)
      Observations suggest spring grazing of riparian areas is a good management strategy because of a reduced tendency for cattle to concentrate along streams during that season. In this study, June cattle distribution was examined within 4 experimental pastures located along Stanley Creek, Sawtooth National Recreation Area, Sawtooth National Forest, in central Idaho. Two pastures were grazed at a light stocking rate and 2 pastures were grazed at a medium stocking rate. Streamside graminoid utilization averaged about 24% under light stocking, while on the adjacent meadow graminoid utilization was 28%. Under medium stocking the average utilization at streamside was 37%, while that on the adjacent meadow was 50%. Residual herbaceous stubble heights under light stocking were 11 to 12 cm for both grazing locations, whereas streamside and meadow stubble heights were 10 cm and 7 cm, respectively, under moderate stocking. Cattle were not disproportionately attracted to the streamside areas during the June period. As stocking rates increased from light to medium, the cattle concentrated most of their additional use on the adjacent drier meadow. Utilization of riparian plant communities during this early summer period had no relationship to the amount of plant moisture content, but was negatively associated with surface soil moisture.
    • Feasibility of grazing sainfoin on the southern Great Plains

      Mowrey, D. P.; Volesky, J. D. (Society for Range Management, 1993-11-01)
      Forage is often in short supply on southern Great Plains grasslands during spring because warm-season grasses are dormant or just beginning to grow. Sainfoin (Onobrychis viciifolia Scop.), a non-bloat-inducing legume, can provide forage in semiarid regions during spring when irrigated. A study was conducted to investigate yield, quality, and persistence of sainfoin in a subhumid region of the southern Great Plains without irrigation. Sainfoin was established in 1989 and grazed with steers at early or late bloom growth stages in 1990 and 1991 to remove 50 or 75% of the forage height. Forage yield averaged 2,480 and 4,110 kg ha-1, respectively in 1990 and 1991. Fifty to 80% of sainfoin's forage yield occurred prior to average stocking dates on warm-season pastures for summer grazing. Crude protein concentration averaged 15 and 19% and in vitro digestible dry matter averaged 57 and 62% in 1990 and 1991, respectively. Sainfoin survival was unaffected by grazing treatment through July 1991. After a severe drought from late July through August 1991, sainfoin stands were reduced 22% across treatments (P > 0.05). Sainfoin has potential to complement warm-season pastures in the southern Great Plains, but additional effort is needed to improve plant persistence.
    • Jackrabbit densities on fair and good condition Chihuahuan desert range

      Daniel, A.; Holechek, J.; Valdez, R.; Tembo, A.; Saiwana, L.; Fusco, M.; Cardenas, M. (Society for Range Management, 1993-11-01)
      This study was conducted on Chihuahuan desert range near Las Cruces, in southcentral New Mexico, to determine the relationship of blacktailed jackrabbit (Lepus californicus) densities to good (GC) and fair (FC) range condition. The Soil Conservation Service procedure was used to classify ecological range condition. Line transect procedures were used to estimate jackrabbit populations from July 1988 to December 1990. Concurrently vegetation cover and mean plant height were determined with the line intercept procedure. Jackrabbit densities on the fair condition range were higher (P < 0.10) than those on the good condition range. This difference is attributed to the fair condition range containing more protective cover and preferred forage than good condition range. Jackrabbit abundance showed no season (P < 0.10) or year differences (P < 0.10). Jackrabbits preferred grass-shrub mosaic habitats more than shrubland and grassland habitats. The need for diverse food sources and protective cover were apparently major determinants of habitat selection by jackrabbits. The good condition range contained greater (P < 0.10) grass cover and less (P < 0.10) shrub cover than the fair condition range. Our results indicated that maintaining Chihuahuan desert ranges in good to excellent condition is the best means of achieving lower abundance of jackrabbit populations.
    • Late-summer fire and follow-up herbicide treatments in tallgrass prairie

      Engle, D. M.; Stritzke, J. F.; Bidwell, T. G.; Claypool, P. L. (Society for Range Management, 1993-11-01)
      Research on fire in tallgrass prairie focuses almost exclusively on dormant season fires, primarily in winter and spring. Relatively little is known about the response of tallgrass prairie vegetation to growing-season fires or follow-up management. We evaluated vegetation response of grazed, high-seral tallgrass prairies to herbicides after late-summer burning. Dry matter yields of little bluestem [Schizachyrium scoparium (Michx.) Nash], other perennial grasses, total perennial grasses, and total herbage were significantly reduced by late-summer burning. Tallgrass and annual grass standing crop did not differ between burn treatments. Forb standing crop on burned plots averaged about twice that of unburned plots. Follow-up treatment with 2,4-D[(2,4-dichlorophenoxy)-acetic acid] significantly reduced forb standing crop compared to atrazine [6-chloro-N-ethyl-N'-(1-methylethyl) 1,3,5-triazine-2,4-diamine]. Standing crop of tallgrasses and total perennial grasses was greater on plots treated with 2,4-D than on plots treated with no herbicide or with atrazine. Because late-summer burning did not severely reduce herbage production nor drastically alter community composition for more than 1 year, late-summer burning may be a viable alternative for brush control and for improving wildlife habitat in high-seral tallgrass prairie. If management objectives require reduced forb production and increased perennial grass production following late-summer burning, application of 2,4-D would be an appropriate management practice.
    • Kochia scoparia emergence from saline soil under various water regimes

      Steppuhn, H.; Wall, K. (Society for Range Management, 1993-11-01)
      Kochia scoparia (L.) Schrad. invades disturbed soils and serves as a pioneer species on saline rangelands and sodic mine spoils. The percent germination of kochia seeds declined with increasing salinity, averaging -3.3%/dS/m between 12 and 30 dS/m. The emergence and early survival of kochia seeded into 2 media whose respective saturated-paste extracts averaged 1 and 18 dS/m in electrical conductivity (ECe) were investigated in a greenhouse under simulated rainfall regimes. Water was applied according to 3 average rates: 0.6 mm/day (low); 1.2 mm/day (medium); 2.5 mm/day (high). These rates were administered in 2 phases. Phase I (14 days) involved low and medium on the nonsaline seedbeds, and medium and high on the saline seedbeds. Phase II (42 days) followed sequentially on only the saline soil in Phase-I:II combinations of high-high, high-medium, medium-medium, and medium-high. Kochia seedlings did not emerge under the low rate. Seedlings did emerge from the nonsaline seedbeds when watered at the medium rate, but failed to emerge from the saline seedbeds treated only at this rate. Seedlings emerged from the saline soil under all regimes that included the high rainfall rate. About 30 plants successfully emerged from every 100 seeds sown in the seedbeds where ECe decreased to 15.7 dS/m or less. Despite the severely saline seedbed, kochia emerged within 3 days at a rate of 8 plants/day under the Phase I high regime because the water apparently diluted saline seedbed-solutions sufficiently for germination to occur. Phase II of the medium-high regime stimulated a similar response but only after 13 days under the wetter rate. Kochia's germination and emergence favor its addition to seed mixtures designed to establish forages in saline soils.
    • Long-term effects of woody vegetation management on seasonal body condition of northern bobwhites

      Boren, J. C.; Lochmiller, R. L.; Leslie, D. M.; Engle, D. M. (Society for Range Management, 1993-11-01)
      We investigated effects of season and brush management on body condition of northern bobwhites (Colinus virginianus) in the Cross Timbers ecosystem of central Oklahoma. Quail were collected seasonally and body condition assessed by necropsy and analysis of percent fat, protein, and ash in the carcass. Brush management by herbicide, herbicide + fire, and mechanical removal had minimal long-term effects on body condition. However, we found significant seasonal differences in weights of the gizzard, gizzard fat, liver, and lipid reserves (body and gizzard fat). With respect to condition, we concluded that northern bobwhites derived no long-term benefits from brush management programs in the Cross Timbers ecosystem of central Oklahoma.
    • Native or seeded rangeland for cows with high or low milk production

      Adams, D. C.; Staigmiller, R. B.; Knapp, B. W.; Lamb, J. B. (Society for Range Management, 1993-11-01)
      Multiparous cows (n = 91, 1986; n = 92, 1987) were selected from 2 populations to obtain cattle with high and low milk production. After March-April calving, high and low producing cows grazed either native range (treatment 1) or seeded range (treatment 2) until weaning in September. Seeded range included paddocks of crested wheatgrass (Agropyron desertorum, Fisch. ex [Link]Schult), contour furrowed native range interseeded with "Ladak" alfalfa (Medicago Sativa L.), and Russian wildrye grass Psathrostachys juncea[Fisch.]Nevski.). In treatment 2, crested wheatgrass was grazed mid-April to 17 June, followed by contour furrowed rangeland 18 June to 5 August, and ended with Russian wildrye 6 August to weaning (mid-September). Data were analyzed as a split plot with treatment and year in the main plot and cow type in the subplot. Number of cows exhibiting estrus before the beginning of the breeding season and fall pregnancy rate were not influenced (P > 0.05) by range treatment. Twelve-hour milk production during May, June, August, and September ranged from 11.3 to 6.8 kg and 7.6 to 3.9 kg for high and low producing cows, respectively. Cows with high milk production lost body condition during and after the breeding season, whereas cows with low milk production maintained body condition during the same period. Live weight gain of calves was greater (P < 0.01) for cows with high production than cows with low production but was not affected (P > 0.05) by range treatment. We concluded that native and seeded ranges were of similar nutritive value for cows with high and low milk production and that cows with high milk production may have greater nutrient requirements during late summer-early fall than what was provided by native or seeded ranges. Protein may be the primary limiting nutrient in forages during the late summer for lactating cows grazing Northern Great Plains range.
    • Overstory-understory relationships for broom snakeweed-blue grama grasslands

      McDaniel, K. C.; Torell, L. A.; Bain, J. W. (Society for Range Management, 1993-11-01)
      Data collected over a 11-year period at 2 study areas near Vaughn and Roswell, N.M. were used to define equations that relate grass biomass to the amount of broom snakeweed (Gutierrezia sarothrae [Pursh] Britt. & Rusby) occupying blue grama (Bouteloua gracilis [H.B.K. Lag]) rangeland over time. A 5 parameter sigmoidal growth equation and a negative exponential equation best expressed the relationship between understory grass biomass and overstory broom snakeweed biomass. Explanatory variables included realized precipitation during the second April to June) and third (July to September) quarters, which coincides primarily with warm-season grass growth. Minimum suppression of grass biomass occurred with complete elimination of broom snakeweed, suggesting control strategies with high overstory mortality will likely be most beneficial to understory production.
    • Steer performance on native and modified Northern Great Plains rangeland

      Heitschmidt, R. K.; Volesky, J. D.; Haferkamp, M. R.; Currie, P. O. (Society for Range Management, 1993-11-01)
      Research was conducted to quantify the effects of various range improvement treatments on diet quality and summer weight gain of steers grazing semiarid rangeland from 1983 through 1988. Treatments were: no treatment (i.e., control), contour furrowing, intertilling with a prototype range improvement machine and combinations of the range improvement machine, nitrogen fertilization, legume interseeding, or brush control. Diet quality was measured in 1987 and 1988. Data were analyzed using vitrious repeated measures analysis of variance models. Various relationships between the animal performance data and previously published herbage standing crop data were examined using standard correlation procedures. There were no significant treatment (P > 0.17) or year by treatment (P > 0.82) interaction effects relative to average daily gains, total gain steer-1, and gain ha-1. However, all year effects were significant (P < 0.05) for these variables with years accounting for about 67% of the observed variation in weight gains. Percentage crude protein in diet samples was greater in 1987 compared to the severe drought year of 1988 and was greater at the beginning than at the end of each grazing season (P < 0.05). However, in vitro dry matter digestibility of diets was greater in 1988 than 1987 primarily because digestibility of diets increased in 1988 from the beginning to the end of the trial. Significant correlations between gain steer-1 and gain ha-1 and early season total and perennial cool-season grass standing crop estimates indicated some rudimentary information is available at the beginning of each grazing season for predicting season-long weight gains. Because average daily gains during late spring and early summer were several fold greater than late season gains in all years except one, it is hypothesized that intensive early stocking strategies may be appropriate for stocker cattle grazing in the Northern Great Plains.
    • Technical Note: Persistence and yield of ladino white clover in southeastern Louisiana

      Johnson, M. K. (Society for Range Management, 1993-11-01)
      Ladino white clover (Trifolium repens L.) is usually reestablished annually for cool-season and early warm-season pasture improvement. Careful pasture management during summer can encourage persistence of stolons so that renovation and reseeding may not be needed for subsequent grazing. Ladino white clover might be manageable for both cool- and warm-season grazing if grass competition is controlled. Both cool- and warm-season yields of persisting ladino white clover exceeded that of new plantings by an average (+/- SE) of 180 +/- 41%. Winter yields of persisting swards averaged 5,250 +/- 350 kg/ha while those of new plantings were only 1,379 +/- 182 kg/ha. Average standing crop of persisting and new plantings was 3,497 +/- 724 and 2,500 +/- 378 kg/ha, respectively, from June through September. Suppression of warm-season competition leading to ladino white clover persistence may produce economic and soil conservation advantages. The greatest advantage of managing for persistence appeared to be increased forage for winter grazing.
    • Tobosa tiller defoliation patterns under rotational and continuous stocking

      Senock, R. S.; Anderson, D. M.; Murray, L. W.; Donart, G. B. (Society for Range Management, 1993-11-01)
      Continuous low animal density grazing of tobosa [Hilaria mutica (Buckl.) Benth.] in the northern Chihuahuan desert results in nonuniform forage utilization. Stocking smaller tobosa rangeland paddocks with high numbers of cattle for short periods of time may facilitate more uniform forage utilization. Two grazing periods in each of 2 consecutive years were monitored to investigate the frequency with which tobosa tillers were defoliated and the intensity of defoliation (change in height) in relation to grazing pressure under high-density seasonal rotational and low-density seasonal continuous grazing. Approximately 40% of tiller height, including leaves, was removed at each defoliation in the rotational treatment, while intensity of defoliation per grazing event remained consistent. In the continuous treatment, amount of tiller removed varied widely and was not consistent among the 4 periods. Percentage of tillers defoliated in the rotational treatment was always greater than 75%, and always less than 30% in the continuous treatment. The probability that a tiller would be grazed at least once in the rotational treatment was more than twice as great as in the continuous treatment. However, within the rotational treatment, the probability of multiple grazing events (greater than or equal to 2) on an individual tiller was less than the probability of a tiller being grazed just once. In general, high-density rotation grazing promoted more uniform. forage utilization of tobosa than low-density continuous grazing.
    • Sequential sampling of surface-minded land to assess reclamation

      Ames, M. (Society for Range Management, 1993-11-01)
      Yearly, a larger percentage of government regulations are stated in statistical terms. More than simple techniques are sometimes necessary to comply with these regulations, both in analyzing and designing experiments and surveys. The problem considered in this paper is how to efficiently sample a mining site to show that the site has been successfully reclaimed. Different sequential analyses are suggested and a two-stage plan by Stein is recommended and illustrated. This approach allows us to sample with a predetermined probability of detecting a successful reclamation. It is pointed out that the usual sample size formulas are not directly applicable to this problem.
    • Seedling growth of 2 Leucaena species

      Dovel, R. L.; Vietor, D. M.; Hussey, M. A. (Society for Range Management, 1993-11-01)
      Seed of Leucaena leucocephala (Lam) Dewit variety K-8 and L. retusa Gray variety Yellow Puff were germinated in growth chambers maintained at 10, 25,30, and 35 degrees C. A fifth treatment of 30 degrees C for 13 hours followed by 25 degrees C for 11 hours was also included. Seed were monitored every 4 days for 16 days for percent germination, testa weight, cotyledon weight, hypocotyl weight and length, and radicle weight and length. Yellow Puff exhibited higher maximum germination and a higher germination rate (expressed as percent of germinable seed germinated 4 days after imbibition) than K-8. There was no temperature effect on maximum germination of K-8, while the 35 degrees C treatment substantially reduced germination in Yellow Puff. Despite faster germination, Yellow Puff seedlings elongated slower compared to K-8. Radicle/hypocotyl ratios were similar for both species across all temperatures. Due to heavier seed weight of K-8 than Yellow Puff, testa and cotyledon weights were also heavier. Rate of nutrient reserve mobilization from the tests and cotyledon increased with increasing temperature in K-8, while rate of mobilization of nutrient reserves in Yellow Puff seed declined at temperatures above 30 degrees C.
    • White-tailed deer and cattle diets at La Michilia, Durango, Mexico

      Gallina, S. (Society for Range Management, 1993-11-01)
      Fecal analysis was used to determine the relationships between white-tailed deer (Odocoileus virginianus couesi [Coues and Yarrow]) and cattle diets (Beef Master, Hereford and criollo), in Durango, Mexico. Deer preferred shrub and tree species (85% of the diet), whereas cattle preferred grasses (61%). Although diets varied seasonally, as did forage availability and quality, the same selective forage pattern was maintained throughout the year. There was a significant difference in the use of different plant groups between the 2 herbivores. The diet overlap index (50.51%) suggested competition during the wet season, but forage was abundant (628 kg/ha dry weight biomass compared with 380 kg/ha in the dry season), thus reducing potential conflicts. Deer and cattle can simultaneously forage in this ares without detriment to either species. The vegetation can maintain a stable composition under higher utilization levels when used by 2 herbivores with different forage patterns than when used by only 1 herbivore.