bluuebunny/crossref_metadata_2025 huggingface dataset:
Carbon exchange rates in grazed and ungrazed pastures of Wyoming
Authors: Lecain D. R. , Morgan J. A. , Schuman G. E. ,   Society for Range Management
Published: March 2016

The influence of cattle grazing on carbon cycling in the mixed grass prairie was investigated by measuring the CO(2) exchange rate in pastures with a 13 year history of heavy or light grazing and an ungrazed exclosure at the High Plains Grasslands Research Station near Cheyenne, Wyo. In 1995, 1996 and 1997 a closed system chamber, which covered 1 m(2) of ground, was used every 3 weeks from April to October to measure midday CO(2) exchange rate. Green vegetation index (similar to leaf area index), soil respiration rate, species composition, soil water content, soil temperature, and air temperature were also measured to relate to CO(2) exchange rates of the 3 grazing treatments. Treatment differences varied among years, but overall early season (mid April to mid June) CO(2) exchange rates in the grazed pastures were higher (up to 2.5 X) than in the exclosure. Higher early season CO(2) exchange rates were associated with earlier spring green-up in grazed pastures, measured as higher green vegetation index. As the growing season progressed, green vegetation index increased in all pastures, but more so in the ungrazed exclosure, resulting in occasionally higher (up to 2 X) CO(2) exchange rate compared with grazed pastures late in the season. Seasonal treatment differences were not associated with soil temperature, soil respiration rate, or air temperature, nor was there a substantial change in species composition due to grazing. We hypothesize that early spring green-up and higher early season CO(2) exchange rate in grazed pastures may be due to better light penetration and a warmer microclimate near the soil surface because of less litter and standing dead compared to the ungrazed pastures. When all the measurements were averaged over the entire season, there was no difference in CO(2) exchange rate between heavily grazed, lightly grazed and ungrazed pastures in this ecosystem.
A comparison of methods to determine plant successional stages
Authors: Winslow S. R. , Sowell B. F. ,   Society for Range Management
Published: March 2016

Twenty-six, 0.04 ha macroplots were sampled on 9 range sites in southwestern Montana to compare successional scores and condition classifications of range condition analysis and United States Forest Service (USFS) Ecodata and Ecopac (Strata) analysis methods. Range condition scores (0-100%) and range condition classes (poor, fair, good, excellent) were derived from the traditional Soil Conservation Service range condition analysis method, with the exception that only major decreaser and increaser graminoids and shrubs were individually clipped and bagged. Ecological status scores (1-100%) and ecological condition classes (low, mid, high, very high) were determined with United States Forest Service Ecodata methods. Range condition score means were greater (p < 0.02) than ecological status score means (48% vs 41%). Standing crop biomass affected differences (p < 0.001) between range condition scores and ecological status scores. Lower producing sites had greater range condition scores than ecological status scores and higher producing sites had greater ecological status scores than range condition scores. Range condition classes and ecological condition classes were not independent (p < 0.02). Differences between the 2 methods were attributable to the use of species composition by weight for the range condition analysis and the use of percent canopy cover by Ecodata methods. Rangeland managers trying to determine successional status should realize that range condition analysis and Ecodata methods produce similar condition classes but different condition scores.
Characterization of Siberian wheatgrass germplasm from Kazakhstan (Poaceae: Triticeae)
Authors: Jensen K. B. , Asay K. H. , Johnson D. A. ,   Society for Range Management
Published: March 2016

Siberian wheatgrass [Agropyron fragile (Roth) Candargy] is known for its establishment and persistence on sandy soils under severe water limitations. Morphology, cytology, and forage and seed characteristics were studied on 59 accessions (JA) of Siberian wheatgrass collected on sandy soils in the desert areas of western Kazakhstan. Plants were grown at Nephi, Ut., from 1993 to 1996 and compared with the check cultivars of Vavilov and P-27 Siberian wheatgrass, and Nordan crested wheatgrass [A .desertorum (Fisch. ex Link) Schultes]. All JA-accessions were autotetraploids, 2n= 4x= 28. The most frequently observed meiotic association was 6 bivalents + 4 quadrivalents. The JA-accessions were morphologically diverse, ranging from short to tall in stature and from dark-green, glaucous to blue-green, strongly pubescent. Mean forage yield, crude protein, and dry matter digestibility were generally lower in the JA-accessions than the check varieties. Entry x year interactions were nonsignificant (P> 0.05) for all measured forage variables. Entries were significantly (P < 0.01) different for dry matter production. Seed weight of Vavilov and mean seed weight of JA-accessions were significantly (P < 0.01) greater than that for the check cultivars P-27 and Nordan. Entries that were highly pubescent had the heaviest seed and greatest capacity to emerge from a 7.6-cm planting depth. Seed yield plant -1 was significantly (P < 0.01) lower in the JA-accessions than cultivars Vavilov, P-27, and Nordan. Sufficient variations exist for seed yield, seed weight, seedling vigor, and forage yield within the JA-accessions to allow for the development of an agronomically suitable, drought tolerant Siberian wheatgrass through selection.
Biological control of leafy spurge with introduced flea beetles (Aphthona spp.)
Authors: Kirby D. R. , Carlson R. B. , Krabbenhoft K. D. ,   Society for Range Management
Published: March 2016

Flea beetles (Aphthona spp.) were introduced into leafy spurge (Euphorbia esula L.)-infested rangeland in east-central North Dakota. The study objectives were to evaluate the effects of the introduced insects on leafy spurge cover, density, and yield, and grass and grass-like yield of associated plant communities. Aphthona spp. were released in 1988 and 1989 at 2 sites near Valley City, N.D. Aboveground vegetative sampling for leafy spurge cover, density and yield, and grass and grass-like yield was conducted between 1993 and 1995. Belowground sampling of root density, dry weight and root buds was conducted between the release date and 1995. Aphthona spp. reduced aboveground cover, density and yield of leafy spurge and increased yield of grass and grass-like species. Leafy spurge root density, weight, and number of root buds decreased on insect release sites between release dates and 1995. Reduced stem density of leafy spurge and increased grass and grass-like yield, should enhance cattle use and production from these sites.
Rearing conditions for lambs may increase tansy ragwort grazing
Authors: Sutherland R. D. , Betteridge K. , Fordham R. A. ,   Society for Range Management
Published: March 2016

Grazing by sheep is an accepted method of controlling tansy ragwort (Senecio jacobaea L.), but some flock members seldom eat it. Our objectives were to determine if pre-weaning exposure to tansy ragwort increases later consumption of the plant by lambs, and if confinement with ragwort-eating ewes after weaning facilitates ragwort eating. The sampling periods were Weeks 1, 3, and 12 following weaning. During each period grazing behavior was observed for 1-hour each day and the 24-hour reduction in ragwort volume measured on each of 4 or 5 consecutive days. Lambs exposed to ragwort before weaning removed more ragwort than ragwort-naive lambs during the first 2 sampling periods (P < 0.05). Lambs that grazed with ewes for 11 weeks following weaning ate ragwort more frequently during direct observation, than lambs without ewes during Weeks 3 and 12 (P < 0.05). The ragwort-eating of all lamb groups increased markedly between Weeks 1 and 12 (P < 0.05). This may indicate an increased ability of lambs to consume ragwort with increasing age or an acclimation period during which most lambs come to accept ragwort. Behavioral interventions aimed at increasing the consumption of weeds by lambs may need to take into account age-related differences in toxin tolerances. Exposing lambs to ragwort before weaning and grazing newly-weaned lambs with older ragwort-eating sheep after weaning may increase later ragwort-eating by lambs.
Perceptions and economic losses from locoweed in north-eastern New Mexico
Authors: Torell L. A. , Owen L. P. , McDaniel K. C. ,   Society for Range Management
Published: March 2016

Livestock producers and others knowledgeable about the locoweed problem in northeastern New Mexico were surveyed to obtain the production information needed to estimate economic losses from locoweed (Oxytropis/Astragalus) poisoning. A partial budgeting approach was used to estimate economic losses based on animal performance differences with increasing levels of poisoning. With current production costs and 1990-96 average beef prices, annual locoweed poisoning losses were estimated to be 75 head-1 for moderately poisoned animals, and 282 head-1 for severely poisoned animals. The most common locoweed management strategy used by northeastern New Mexico ranchers was to move animals observed eating locoweed into locoweed-free areas. Rehabilitation of these animals for an extended period before sale was found to decrease economic loss relative to immediate sale. Moderately and severely poisoned animals that are rehabilitated were estimated to gain 14% and 29% less than non-intoxicated animals. Other management options including chemical locoweed control, fencing, and locoweed aversion were found to be economically justified when relatively high locoweed infestations are anticipated.
Early establishment of Douglas-fir and ponderosa pine in grassland seedbeds
Authors: Bai Y. , Thompson D. , Broersma K. ,   Society for Range Management
Published: March 2016

Grassland of interior British Columbia are being encroached upon by Douglas-fir (Pseudotsuga menziesii var. glauca (Beissn.) Franco) and ponderosa pine (Pinus ponderosa Dougl.). A pot experiment placed in the field was conducted to determine the effect of forest and grassland seedbeds on seedling emergence and early establishment of the 2 species with 2 seed collections each. For these seedbeds, structural characteristics were evaluated and the effect of seedbeds water extracts on seed germination was determined. Seedling emergence of both species was significantly reduced by Douglas-fir needles and enhanced by fescue litter and cattle manure compared to mineral soil. The rate of emergence was reduced by Douglas-fir needles and sagebrush litter, and for some collections, by ponderosa pine needles, but was always enhanced by manure compared to mineral soil. Seedling survival was generally not affected by seedbeds. Douglas-fir seedlings emerging earlier in the season survived better, and both Douglas-fir and ponderosa pine seedlings emerging earlier lived longer than these emerging later. Seed germination of ponderosa pine was not affected by the water extract while that of Douglas-fir was reduced by the water extract from sagebrush litter. Therefore, differences in seedling emergence of the 2 species among seedbeds were related more to structural than to chemical characteristics of seedbeds. Successful establishment of the 2 species in grasslands within this region likely relies on the ability of seeds to germinate early in the growing season on seedbeds in which soil moisture is conserved, as summer droughts are severe.
Tiller recruitment patterns and biennial tiller production in prairie sandreed
Authors: Hendrickson J. R. , Moser L. E. , Reece P. E. ,   Society for Range Management
Published: March 2016

Tiller recruitment is an essential process for ensuring the perenniality of grasses. The timing and extent of tiller recruitment and the role of biennial tillers must be documented for key range species. Prairie sandreed [Calamovilfa longifolia (Hook) Scribn.] is an important grass in the Nebraska Sandhills for both ecological functioning and as a forage. The objective of this study was to document tiller recruitment patterns and the occurrence and contribution of current year and biennial tillers to biomass production in prairie sandreed at 2 locations in Nebraska. Tiller recruitment was monitored at 2-week periods throughout the growing season during a 2-year period. Newly emerged tillers were classified as intravaginal, extravaginal, or rhizomatous tillers and marked with colored wire. Prairie sandreed has an unimodal pattern of tiller recruitment and over 50% of the current year tillers emerged by mid-May and 80% by mid-June. Rate of tiller emergence and absolute number of emerged tillers were poorly correlated with short- and long-term precipitation totals (r < 0.3 P > 0.20). The year after new tillers were marked, biennial tillers and tillers initiated during the current-year were counted and clipped in September for biomass determination Biennial tillers made up only 6 and 20% of the total tiller emergence at these locations and were generally only 30% as large as the new tillers. Extravaginal tillers composed over 78% of the biennial tiller population as a result of both their dominance in emerging populations and the higher percentage of tillers that survived the winter. Current year tillers contributed the most to prairie sandreed forage production and their emergence was largely completed by mid-June. The lack of a relationship between tiller recruitment and precipitation patterns, combined with previous studies of prairie sandreed, indicates that tiller recruitment involves a process that begins the previous growing season.
Rotational stocking and production of Italian ryegrass on Argentinean rangelands
Authors: Jacobo E. J. , Rodriguez A. M. , Rossi J. L. ,   Society for Range Management
Published: March 2016

The decreased carrying capacity of Argentinian Flooding Pampa rangelands through the reduction of density of C3 grasses may be partially attributed to continuous stocking. The objective of this study was to evaluated the effectiveness of rotational vs. continuous stocking to improve winter forage production by incrementing the density of Italian ryegrass (Lolium multiflorum Lam.). Under rotational stocking, ryegrass seedlings established almost 2 months earlier in the fall and tiller density was 3-fold higher in winter than under continuous stocking. Aerial net primary productivity of C3 grasses was approximately 2-fold greater under rotational compared with continuous stocking in the first and second years. This substantial increase in winter productivity supported almost 2-fold increase in stocking rate (from 0.6 to 1.0 AU ha-1).
A method for estimating cattle fecal loading on rangeland watersheds
Authors: Tate K. W. , Atwill E. R. , McDougald N. K. ,   Society for Range Management
Published: March 2016

Water quality contamination by pathogens and nutrients from cattle fecal deposits is a concern on rangeland watersheds. The temporal and spatial deposition of fecal material relative to storm events and water-bodies determines much of the risk a grazing scheme presents to water quality. The objective of this study was to develop and evaluate a comparative technique to estimate cattle fecal loading across a watershed through time. Once the method was developed, dry and wet season trials were conducted on a 138 ha experimental rangeland watershed at the San Joaquin Experimental Range in 1996-97. Fifty-four permanent 40 m2 belt transects were established across the watershed. Observers ocularly assigned a rank of 1 (smallest diameter) to 5 (largest diameter) to each fecal deposit within a transect. A regression relationship was developed to predict fecal deposit dry weight by rank. Load per transect was calculated as the total weight of all fecal deposits in a transect. All fecal deposits in transects were collected and actual fecal load determined. The comparative yield methodology was successfully adapted to estimate rangeland fecal loading. Regression relationships predicting fecal deposit dry weight by ranks were highly significant for all observers (p < 0.001). The R2 values ranged from 0.97 to 0.99 in the dry season and 0.89 to 0.94 in the wet season. There was no significant difference between the weighted fecal load estimate and the estimates of observers using the comparative method (P < 0.05). This method provides a rapid, simple method for estimating spatial and temporal livestock fecal loading on rangeland watersheds.
Nutritive value and aversion of honey mesquite leaves to sheep
Authors: Baptista R. , Launchbaugh K. L. ,   Society for Range Management
Published: March 2016

Honey mesquite (Prosopis glandulosa Torr.) is an invasive native plant that is abundant in Mexico and the Southwestern United States. We initiated 2 studies to determine if: 1) mesquite could provide valuable forage for domestic herbivores; and 2) if mesquite causes conditioned flavor aversions in ruminants. An in vivo digestion trial was completed with 15 lambs assigned to diets of 0, 5, 10, 15, or 20% dried mesquite leaves mixed with alfalfa hay to measure effects of mesquite on intake and digestion. Proportions of mesquite leaves >5% of the diet negatively affected dry matter (DM) intake, nitrogen (N) balance, energy balance and weight gain. Mesquite intake was highest at the 5% level averaging 1.81 g kg-1 body weight (BW), mesquite intake of the other mesquite-containing diets averaged 0.78 g kg-1 BW. Apparent digestibility was not affected by the level of mesquite in the diet. An in situ digestion trial did however, reveal that pure alfalfa was more digestible than mesquite leaves. A conditioned flavor aversion (CFA) trial tested the effect of post-ingestive feedback from mesquite on the intake of a novel food (rye). Lambs were offered rye and then ground mesquite was infused into their rumens by esophageal tube. Twenty one lambs were assigned to 3 dosing treatments: 0 (control), 3.0 (low), or 4.5 (high) g of mesquite per kg BW. Two days after dosing, lambs that received mesquite infusions ate less rye than controls indicating the formation of a CFA. The aversion to rye persisted for at least 2 days. The high dose of mesquite also decreased intake of the alfalfa basal ration for at least 3 days and resulted in persistent diarrhea in lambs. Chemical analysis of mesquite leaves revealed similar nutritive quality (crude protein, gross energy, and fiber) as mature alfalfa. However, to exploit the forage value of mesquite, the allelochemicals that cause flavor aversions and other negative digestive consequences need to be identified and overcome.
Range condition, tenure, management, and bio-physical relationships in Sonora, Mexico
Authors: Coronado-Quintana J. A. , McClaran M. P. ,   Society for Range Management
Published: March 2016

The objective of this study was to describe the relationship among range condition scores, tenure system, management practices and bio-physical variables for 107 communal ejido ranches and 373 private ranches in Sonora, Mexico. The data was obtained from assessments of range condition and recommended carrying capacity for individual ranch units that were completed between 1973 and 1993 by the Comision Tecnica para la Determinacion de Coeficientes de Agostadero. Variables measured were range condition, land tenure (communal ejido or private ranch), management characteristics (human density, livestock stocking rate, ranch size, and infrastructure condition), and bio-physical characteristics (rangeland site quality and precipitation in the year of assessment). We used a combination of simple, univariate chi-square analyses and more complex, multi-variate ordered logistic regression analyses to assess the relationships among these variables. There was no evidence from the logistic regression analysis that range condition of ranches in Sonora was related to the ejido or private tenure systems. Infrastructure condition was different between the 2 tenure systems, and infrastructure condition was positively related to range condition for both ejido and private ranches. Based on the univariate and multivariate analyses, precipitation amounts in the year of assessment was less for private ranches, and range condition on private ranches was more sensitive to precipitation than ejido ranches. Compared to estimates made in the 1960's and 1970's in other parts of Mexico, we found there to be less of a difference in stocking rate between the more lightly stocked private ranches and more heavily stocked ejido ranches, and generally good condition infrastructure on all ranches. The important relationship between precipitation and range condition implies that range condition assessments should be done over many years to produce estimates of trend that can be compared across wet and dry years.
Effects of biosolids on tobosagrass growth in the Chihuahuan desert
Authors: Jurado P. , Wester D. B. ,   Society for Range Management
Published: March 2016

Little information is available about seasonal application and carry-over effects of biosolids application to semi-arid grasslands. Biosolids rates of 0 (control), 7, 18, or 34 Mg ha-1 were topically applied to tobosagrass (Hilaria mutica (Buckl.) Benth.) experimental plots in a Chihuahuan desert grassland in western Texas. Biosolids were applied twice in 1994, for one-year-only, either in winter-and-summer (WS), or spring-and-summer (SS) seasons. Half of the plots were irrigated every summer for 4 years (1994-1997). Tobosagrass standing crop (herbage yield) and total Kjeldahl nitrogen concentration (plant %TKN) were measured every year during the 4 years of the study (1994-1997). An increase in biosolids rate increased tobosagrass herbage yield linearly during the 4 growing seasons. Linear and quadratic responses to biosolids rates were observed in %TKN during the experiment. Irrigation increased tobosagrass herbage yield. Irrigation decreased %TKN in 1995 and 1996 and had no influence during the other years. Winter-and-summer applications increased herbage yield more than spring and summer applications in 3 out of 4 years. Spring-and-summer applications increased %TKN more than winter and summer applications only in 1996. Carry-over effects on tobosagrass herbage yield and %TKN were observed in the second, third, and fourth growing seasons after biosolids application. Twice-a-year application of biosolids for 1-year-only offers an excellent means to improve tobosagrass productivity and forage quality.
Revegetating spotted knapweed infested rangeland in a single entry
Authors: Sheley R. L. , Jacobs J. S. , Lucas D. E. ,   Society for Range Management
Published: March 2016

Introducing and establishing competitive plants is essential for the successful management of spotted knapweed (Centaurea maculosa Lam.) infested rangeland where a desirable understory is absent. Our objective was to determine a herbicide-mix that would maximize grass establishment in spotted knapweed-cheatgrass (Bromus tectorum L.) bluegrass (Poa pratensis L.) infested rangeland in a single fall application. On 2 sites in Montana, 8 herbicide treatments [none, glyphosate (N-[phosphonomethyl] glycine) at 0.5 kg a.i. ha(-1), picloram (4-amino-3,5,6-trichloropicolinic acid, potassium salt) at 0.14 kg a.i. ha(-1), picloram at 0.28 kg a.i.ha(-1), clopyralid (3,6-dichloro-2-pyrdinecarboxylic acid, monoethanolamine salt) at 0.21 kg a.i. ha(-1) plus 2,4-D (2,4-dichlorophenoxyacetic acid) at 1.12 kg a.i. ha(-1), picloram at 0.14 kg a.i. ha(-1) plus glyphosate at 0.5 kg a.i. ha(-1), picloram 0.28 kg a.i. ha(-1) plus glyphosate at 0.5 kg a.i. ha(-1), and clopyralid 0.2 kg a.i. ha(-1) plus 2,4-D at 1.12 kg a.i. ha(-1) plus glyphosate 0.5 kg a.i. ha(-1)] and 3 seeded grass species ['Luna' pubescent wheatgrass [Thinopyrum intermedium (Host) Barkworth D.R. Dewey], bluebunch wheatgrass [Pseudorogneria spicata (Pursh.) Love], and 'Bozoyski' Russian wildrye [Psathyrostachys junceae (Fisch.) Nevski] were applied in a split-plot design with 4 replications in the late-fall of 1994 and 1995. Spotted knapweed and grass density were measured in 1995, 1996, and 1997, and biomass was measured in 1997 at peak standing crop. Density data were analyzed as a split-split-plot in time, and biomass data were analyzed as a split-plot using analysis of variance. By the end of the study, picloram applied at either 0.14 or 0.28 kg a.i. ha(-1) in the late-fall consistently yielded lowest spotted knapweed density and biomass. Initially, glyphosate alone lowered spotted knapweed density and increased grass biomass compared to that of the control. However, glyphosate treated plots had more spotted knapweed and less seeded grass established by the end of the study. 'Luna' pubescent wheatgrass consistently yielded the high test density and biomass of the seeded grasses. We believe a single-entry revegetation program applying picloram in late-fall combined with a fall-dormant seeding will maximize seedling establishment in spotted knapweed infested rangeland.
Comparative rumen and fecal diet microhistological determinations of European mouflon
Authors: Chapuis J. L. , Boussés P. , Pisanu B. ,   Society for Range Management
Published: March 2016

The population of European mouflon (Ovis musimon Pallas) established on an island of the sub-Antarctic Kerguelen archipelago is characterized by a demographic cycle. Every 2-5 years, there is a massive winter mortality due to food shortage. A good knowledge of food resources utilization appeared essential to understand the population growth dynamics. We investigated the validity of the microhistological analysis of feces by a comparative analysis of 30 paired rumen and fecal samples collected in winter. Sixteen and 17 food items were identified respectively in rumen and fecal samples. Most fragments could be accurately determined because plant diversity was low. Both methods gave similar results Though quantitative differences appeared between methods for some items, the same 4 major food constituents were identified in relatively close proportions in both rumen and fecal samples. There is a risk of slight overestimation of annual meadow-grass (Poa annua L.) and mosses in feces, and of Azorella selago Hook. f. in the rumen.
Lignin and fiber digestion
Authors: Moore K. J. , Jung H. J. G. ,   Society for Range Management
Published: March 2016

Lignin is a polymer formed from monolignols derived from the phenylpropanoid pathway in vascular plants. It is deposited in the cell walls of plants as part of the process of cell maturation. Lignin is considered an anti-quality component in forages because of its negative impact on the nutritional availability of plant fiber. Lignin interferes with the digestion of cell-wall polysaccharides by acting as a physical barrier to microbial enzymes. Lignification therefore has a direct and often important impact on the digestible energy (DE) value of the forage. There are a number of plant-related factors that affect lignification in individual plants and plant communities. Lignification is under genetic control and there are considerable differences in lignin concentration and composition among species and even genotypes within species. Genetic differences in lignification are first expressed at the cellular level and are affected by biochemical and physiological activities of the cell. As cells differentiate, differences in lignification occur depending on the tissues and organs being developed. Lignification tends to be most intense in structural tissues such as xylem and sclerenchyma. Plant organs containing high concentrations of these tissues, such as stems, are less digestible than those containing lower concentrations. The relative proportion of lignified tissues and organs typically increases as plants mature so there is often a negative relationship between digestibility and maturity. All of these plant processes respond to environmental factors that can affect the extent and impact of lignification. Temperature, soil moisture, light, and soil fertility can have either direct or indirect effects on lignification. The most useful management practices for minimizing the negative effects of lignification are manipulation of the plant community such that it contains more desirable species and harvest management to maintain plants in a vegetative stage of development.
Effects of proanthocyanidins on digestion of fiber in forages
Authors: Reed J. D. ,   Society for Range Management
Published: March 2016

The ability of proanthocyanidins (PA) to form insoluble complexes with proteins and polysaccharides affects fiber digestion and analysis. This review discusses these effects in relationship to the application of the detergent system of forage analysis. A fraction of the PA in plants remains after extraction for analysis. Insoluble PA may be a natural part of the plant cell wall or may be insoluble because of high molecular weight and post harvest reactions. These reactions increase the amount of insoluble PA and decrease the amount of soluble PA. The butanol-HCl assay is the most suitable method for analysis of insoluble PA. Insoluble PA are associated with negative apparent digestion coefficients for acid-detergent lignin (ADL), neutral-detergent insoluble N and acid-detergent insoluble N. The addition of sodium sulfite to neutral detergent eliminates insoluble PA from NDF. However, the addition of sodium sulfite to neutral detergent will give misleading results in relationship to true digestibility of protein. The difference between fiber fractions that are prepared with and without the addition of sodium sulfite to neutral-detergent may estimate the amount of PA/protein complex associated with NDF. A better understanding of the relationship between PA structure and function is necessary to manipulate PA in forages through breeding or genetic engineering. The interaction between PA and fiber analysis and digestion is an important component of this research.
Immigrant' forage kochia seed viability as impacted by storage methods
Authors: Stewart A. , Anderson V. J. , Kitchen S. G. ,   Society for Range Management
Published: March 2016

Immigrant' forage kochia (Kochia prostrata (L.) Schrad.) is a valuable introduced subshrub, often used in reclamation plantings and seedings on western rangelands. Seedling establishment is best from fresh seed; however, many users plant stored seed and experience poor seeding success. One cause for failure is loss of seed viability in storage. Forage kochia seed was harvested on 4 dates in fall 1996 from 2 sites (wildland and irrigated) and tested for viability when fresh and after storage treatments. Storage treatments included low and high seed water contents (2-6% and 12-16%), cold and warm storage temperatures (2 degrees and 25 degrees C), and duration of storage (4, 8, and 12 months). Mature, highly viable forage kochia seed remains viable in storage longer than seed harvested prematurely. Low seed water content (2-6%) is essential to preserving maximum seed viability. Storing seed at a cold temperature (2 degrees C) is also helpful in maintaining viability.
Seed recovery and germination of reseeded species fed to cattle
Authors: Doucette K. M. , Wittenberg K. M. , McCaughey W. P. ,   Society for Range Management
Published: March 2016

Cattle have the potential to act as a low cost alternative for seed dissemination of valuable native species. Data collected from this trial was used to compare seed recovery, rate of passage and viability following ingestion and excretion of 7 plant species. Woods rose (Rosa woodsii Lindl.), snowberry (Symphoricarpos albus L.), purple prairie clover (Petalostemom purpureum Vent.), birdsfoot trefoil (Lotus corniculatus L.), western wheatgrass (Pascopyrom smithii Rydb A. Love, formerly known as Agropyron smithii Rydb.), green needlegrass (Nassella viridula Trin.), and yellow coneflower (Ratibida columnifera Nutt.) seed was used in the study. Two steers were fed a seed-free diet consisting of fresh cut vegetative Kentucky bluegrass (Poa pratensis L.)-alfalfa (Medicago sativa L.) forage. Following a 13 day adjustment period to the diet, steers were fed a single dose of a known number of seeds, and total feces collection was conducted for 168 hours post dosing. Fecal sub-samples were subjected to a stacked screen washing procedure for seed recovery and analysis. Seeds from both pre- and post-ingestion were tested for hard seededness, firm ungerminated seed, and germination. Seed recovery varied between seed types, ranging from 5.9% of total ingested seed for western wheatgrass, to 86.3% for Woods rose. Excretion patterns for ingested seed varied between seed types, with 50% of excreted seed being recovered between 30 to 54 hours post-dosing. Seed ingestion and passage through the digestive tract reduced viability. Cattle dissemination of viable seeds (as a % of ingested) such as Woods rose (77.4) and snowberry (69.3), would be a feasible method of delivering large numbers of viable seeds onto selected areas. Dissemination of birdsfoot trefoil (17.5), green needlegrass (11.9), and purple prairie clover (7.2), yellow coneflower (3.8), and western wheatgrass (1.3), using cattle would be less efficient, implementation should be based on seed access and cost.
Hydrologic responses of a montane riparian ecosystem following cattle use
Authors: Flenniken M. , McEldowney R. R. , Leininger W. C. ,   Society for Range Management
Published: March 2016

Riparian areas link streams with their terrestrial catchments and decrease water pollution by trapping sediments from upland sources before they reach streams or lakes. Livestock grazing in riparian areas is a controversial practice. If not properly managed, cattle can cause degradation to both the riparian zone and adjacent water body. Vegetative, soil microtopographical, microchannel and hydrograph parameters were measured in a montane riparian community in northern Colorado to quantify the effects of cattle on overland flow and runoff characteristics. Treatments were cattle grazing plus trampling, cattle trampling, mowing, and a control. Water was applied to plots (3 m x 10 m) at a rate of 100 mm hr(-1) using a rainfall simulator. Concurrently, overland flow was introduced at the upper end of the plots at an equivalent rate of 25 mm hr(-1). A high intensity-short duration grazing treatment was used for the cattle-treated plots. Reduction in vegetation stem density and aboveground biomass by cattle decreased microchannel sinuosity and drainage density. Cattle-treated plots had greater flow velocities and depths in microchannels compared with mowed and control plots. Reduced stem density and aboveground biomass by grazing left fewer obstacles to divert flows, which decreased microchannel sinuosity and drainage density. Flows were concentrated into fewer microchannels with deeper flows. Microchannel characteristics were not significant factors affecting total runoff. Stem density and rainfall intensity were the most important factors in predicting runoff characteristics and total runoff. Results from this study have improved our understanding of flow and runoff processes following cattle use of a riparian ecosystem.
Autumn and spring drought periods affect vegetation on high elevation rangelands of Turkey
Authors: Koç A. ,   Society for Range Management
Published: March 2016

The amount and temporal distribution of precipitation received is of critical importance for regrowth and plant production on rangelands. The effects of drought in the autumn, and spring/summer, as they affected sheep fescue (Festuca ovina L.) dominated vegetation in Eastern Anatolia, Turkey, were examined between 1996 and 1998. Artificial drought was created using polyethylene rain-out shelters. The experiment was a randomized complete block design with 3 replications with a split-plot arrangement of treatments. Main plots included 2 autumn treatments: imposed artificial autumn-drought or a 40 mm of additional water plus rain. Sub-plots contained 4 treatments: artificial drought in May, June, July, or full spring rainfall. The number of reproductive shoots, aboveground biomass production, protein content, protein yield, canopy coverage and botanical composition were determined. Reproductive shoot numbers were reduced from 617 to 31 m(-2) when plants entered winter without autumn regrowth as a result of autumn-drought. Plots subjected to drought in the autumn had aboveground biomass of 424 kg ha(-1). Protein content of forage, crude protein yield and water use efficiency (WUE) were 11.6%, 49 kg ha(-1) and 1.5, respectively. These were compared with 1,038 kg ha(-1), 9.6%, 99 kg ha(-1), and 2.4, respectively, for plots received normal autumn precipitation in addition to 40 mm of additional water. Aboveground biomass production increased as short-term drought in spring was delayed but WUE was decreased. Autumn-drought had no effect on the proportion of grasses, but reduced legumes and resulted in an increase in other species. Spring/summer-drought had no effect on legumes but, as the onset of drought was delayed, grasses decreased and other species increased in composition. Autumn-drought reduced canopy coverage from 34.7% to 23.8% but spring drought had a negligible effect. Results indicated that autumn precipitation was crucial for productivity of these high elevation rangelands.
Economics of managing mesquite in north Texas: A sensitivity analysis
Authors: Teague W. R. , Ansley R. J. , Kreuter U. P. ,   Society for Range Management
Published: March 2016

This paper presents a comparative simulation analysis of the economics of prescribed fire and aerially applied root-killing herbicide treatment as methods for maintaining livestock productivity on rangeland in the Texas Rolling Plains. A "no-treatment" scenario is used as the base for comparison. In almost all the simulated scenarios both herbicide application and prescribed burning were economically feasible since net present values were > 0 and benefit/cost ratios were > 1. However, the net present values for prescribed fire were much higher that those for the herbicide treatment even with a lower increase in carrying capacity with burning. The cost of herbicide would have to be less than half the current cost of 57 ha(-1) before it would be economically competitive with fire in controlling mesquite. If cattle numbers were not increased after treating brush, burning had an even greater net present value and benefit/cost ratio advantage over herbicide treatment than if cow numbers were increased after treatment. Even if fences have to be constructed to implement adequate deferment for burning, the net present value and benefit/cost ratios of the fire option were higher than those for herbicide scenarios. This analysis indicates that there is an economic advantage to using fire wherever possible, and use of herbicides is restricted to those instances when fine fuel amount is < 1,700 kg ha(-1) yr(-1) when fire is not a viable option. The analyses indicate the economic response is most sensitive to the treatment effect on wildlife income.
Redberry juniper canopy cover dynamics on western Texas rangelands
Authors: Ueckert D. N. , Phillips R. A. , Petersen J. L. ,   Society for Range Management
Published: March 2016

Knowledge of the rate woody plant canopy cover increases is essential for understanding the ecology of rangeland plant communities, determining the economic feasibility of brush management practices, and for scheduling initial and maintenance control practices. We determined rates of change in redberry juniper (Juniperus pinchotii Sudw.) canopy cover from the mid 1950s through the late 1990s at 5 locations in western Texas on rangeland that had been chained or grubbed for juniper control and on adjacent untreated areas. Juniper cover was estimated from aerial photographs by the line intercept method using a 10-X monocular lens with a vernier. Juniper cover increased at 0.35 +/- 0.06 percentage units year(-1) on untreated sites and at 1.01 +/- 0.07 percentage units year(-1) following chaining or grubbing. Juniper cover returned to pre-treatment levels in an average of 20 years (range 11 to 25) following chaining or grubbing. Herbage production on untreated rangeland was predicted to decline slowly (2.4 to 5.0 kg ha(-1) year(-1)) as juniper cover increased from 6 to 14% and rapidly (> 8 kg ha(-1) year(-1)) as juniper cover increased from 30 to 38%. Herbage production was predicted to decline at a constantly increasing rate following mechanical control of juniper, from < 2 kg ha(-1) year(-1) in year 1 to 23 kg ha(-1) year(-1) in year 29. Potential additional livestock carrying capacity due to juniper control would be under estimated by more than 40%, assuming forage production without treatment remained constant during the entire planning horizon of an economic analysis. To avoid significant reductions in livestock carrying capacity, redberry juniper control should be implemented before its canopy cover exceeds about 20%.
Journal of Range Management, Volume 54, Number 6 (November 2001)
Authors:   Society for Range Management
Published: March 2016

Complete digitized issue.
Rangeland management under uncertainty: A conceptual approach
Authors: Batabyal A. A. , Godfrey E. B. ,   Society for Range Management
Published: March 2016

A conceptual approach is commonly needed to provide guidance for developing new strategies concerning the use and management of renewable resources such as rangelands. The theoretical model constructed in this paper captures the essential aspects of dynamic and stochastic issues associated with the management of rangelands. We discuss the connections between the model and range policy. Specifically, we point out scenarios in which there is a limited role for policy. This is compared to scenarios when policy has a significant role to play in ensuring the sustainable use of rangelands. Finally, we suggest 2 ways in which our approach might be extended and used in a practical application.
Quality of forage stockpiled in Wisconsin
Authors: Hedtcke J. L. , Undersander D. J. , Casler M. D. ,   Society for Range Management
Published: March 2016

Stockpiling forage is a commonly used method to extend the grazing season in the southern U.S.A. However, there is little data on stockpiled forage in the upper Midwest. This study was conducted to determine the quality changes of 7 stockpiled cool-season grasses [early and late maturing orchardgrass, Dactylis glomerata L., quackgrass, Elytrigia repens (L.) Desv. Ex. Nevski, reed canarygrass, Phalaris arundinacea L., smooth bromegrass, Bromus inermis Leyss., tall fescue, Festuca arundinacea Schreb., and timothy Phleum pratense L.], with and without N fertilizer, in Wisconsin. Forage was sampled at 3 offseason dates at 3 sites. To determine if N improved forage quality, 4 N-fertilizer treatments were imposed: 0 or 67 kg N ha(-1) applied at start of stockpiling and 2 treatments totaling 168 kg N ha(-1) applied in the fall and spring. Over winter, crude protein (CP) decreased from 116 to 107 g kg(-1), neutral detergent fiber (NDF) increased from 594 to 667 g kg(-1), acid detergent fiber (ADF) increased from 367 to 435 g kg(-1), and in vitro organic matter digestibility (IVOMD) fell from 734 to 655 g kg(-1). Nitrogen fertilizer improved CP in most environments but generally did not affect IVOMD, NDF, or ADF. Smooth bromegrass and quackgrass ranked highest in CP concentration and tall fescue ranked lowest. Timothy and late-maturing orchardgrass ranked highest in IVOMD while quackgrass and reed canarygrass consistently ranked lowest. Quality of all stockpiled forage studied can maintain livestock such as beef cattle or dry dairy cows over winter if the forage is accessible and adequate animal stocking density is maintained.
Grazing impacts on litter and roots: Perennial versus annual grasses
Authors: Mapfumo E. , Naeth M. A. , Baron V. S. ,   Society for Range Management
Published: March 2016

Soil carbon (C) and nitrogen (N) storage in grasslands is a function of litter and root mass production. Research on how annual grasses compare with perennials for above ground and below ground mass production, and contributions to the soil C pool under pasture management is scarce. The objective of this research was to evaluate grazing intensity effects on litter and root mass, C and N pools of perennial grasses, smooth bromegrass (Bromus inermis L.) and meadow bromegrass (Bromus riparius Rhem.), and the annual grass, winter triticale (X Triticosecale Wittmack). Litter mass and C pool for the perennial grasses were greater than those for triticale. Litter C and N pools generally decreased with increased grazing intensity. Root mass was greater for the perennial grasses than for triticale at all grazing intensities. Meadow bromegrass generally produced more root mass than smooth bromegrass. Root C and N pools for triticale were 31 and 27%, respectively, of that for the perennial grasses. Estimated total C contribution (roots and litter) to the resistant soil organic C pool was 1.5 times greater for light compared to heavy grazing. Total C (litter + root) contribution for perennial grasses was 2.7 times greater than that for triticale. Perennial grasses provided a larger litter base and root system that promote greater storage of C in the soil compared with triticale.
Effects of top-soil drying on saltcedar photosynthesis and stomatal conductance
Authors: Mounsif M. , Wan C. , Sosebee R. E. ,   Society for Range Management
Published: March 2016

Phreatophytes are trees and shrubs with deep roots tapping the water tables. As such they are presumed to be able to tolerate a water deficit in the top soil. Growth of some phreatophytes is decoupled from environmental factors such as incident precipitation. This study examined the effects of surface soil drying on gas exchange and stomatal conductance of a riparian phreatophyte Tamarix gallica L. (saltcedar) during 2 consecutive growing seasons in which summer precipitation varied substantially. Daily average gas exchange (A) was 13.5 micromol m(-2) sec(-1) in June and 13.4 micromol m(-2) sec(-1) in September, 1991 when surface soil was wet as compared to the same periods of 1990 in which very little rain occurred (6.44 and 8.08 micromol m(-2) sec(-1), respectively, P < 0.0001). Stomatal conductance (g) or maximal conductance showed a similar trend of photosynthesis. Both average gas exchange and stomatal conductance were correlated with water content in the upper portion of the soil (r = 0.83 to 0.88 for A, P < 0.05 and r = 0.65 to 0.70 for g, P < 0.05) in 1990 (a dry year). The variations in gas exchange or stomatac conductance of saltcedar were mainly caused by water availability in the upper soil layers, not by depth to the water table (0.65 vs 2.74 m). The responses of gas exchange and stomatal conductance to surface soil drying in the phreatophyte saltcedar were similar to that of several crop species [lupin (Lupinus cosentinii Guss. cv. Eregulla), wheat (Triticum aestivum L. cv. Cadensa) and sunflower (Helianthus annuus L.)]. Our data suggest that upon soil re-wetting, when water availability to shallow lateral roots increased, the entire root system of saltcedar was actively involved in water uptake, leading to higher stomatal conductance and photosynthesis.