Journal of Range Management, Volume 39 (1986): Recent submissions
Now showing items 21-40 of 146
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Nutrient Composition of Atriplex Leaves Grown in Saudi ArabiaLeaves of 6 Atriplex species (saltbush) grown in Saudi Arabia were studied for their nutritive characteristics. Crude protein contents varied between 16.7 - 25.2%, crude fat between 1.0 - 1.6%, crude fiber between 7.8 - 10.4%, and ash between 18.5 - 27.2%, on a dry matter basis. A. undulata had the lowest and A. nummularia had the highest protein and fiber contents. Ash content was lowest in A. canescens and highest in A. undulata. The level of Na was extremely low (0.21%) in A. canescens compared to that in the other species (2.38 - 5.57%). The level of K (6.06%) was highest in A. canescens compared to 2.48 - 3.54% in other species. Ca content was significantly higher in A. vesicaria (2.48%) than that in the remaining species (1.12 - 1.50%). Variations in the levels of P, Mg, Fe, Zn, Cu, and Mn were only minor. Sulphur amino acids (methionine + cystine) were the most deficient essential amino acids in all species (chemical score = 45 - 61) while lysine contents were 75 - >100% of the FAO/WHO (1973) reference protein. Predicted digestible dry matter ranged between 74.5 - 78.8% and digestible energy (M Cals/Kg) between 3.215-3.399. These data suggest that Atriplex leaves as a range forage for livestock would have good nutritive value.
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Modeling Evapotranspiration from Sagebrush-Grass RangelandThree models, CREAMS, SPAW, and ERHYM, were used to predict evapotranspiration (ET) from a sagebrush-grass range site in southwest Idaho. Model-predicted ET was compared with ET measured by a lysimeter and ET calculated with a water-balance equation using field-measured soil water and precipitation values. There was generally good agreement between the lysimeter and water-balance calculated ET and between these ET values and model-predicted ET. Maximum averaged daily ET rates were about 2.5 mm for April, May, and June with single day ET values from the lysimeter as high as 5.0 mm. Although the CREAMS predicted ET rates were generally higher than those predicted by SPAW and ERHYM or measured by the water-balanced method, all 3 models were functionally capable of simulating ET from sagebrush-grass range sites. ERHYM was the simplest of the 3 models to operate.
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Miserotoxin Levels In Fertilized Astragalus miser var. serotinusThe effect of fall application of urea fertilizer on toxicity of timber milkvetch was examined in 2 growing seasons at 2 rangeland sites in southern British Columbia. On the grassland site, aerial application of urea at 100 kg N/ha did not affect levels of miserotoxin in timber milkvetch. At the forest clearcut site, 200 kg N/ha reduced toxin levels at later stages of growth in the first growing season. In the second year, however, an increase in the level of miserotoxin was detected at the clearcut.
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Influence of Climatic Conditions on Production of Stipa-Bouteloua Prairie Over a 50-Year PeriodRange forage yields obtained over a 50-year period at the Research Substation near Manyberries in southeastern Alberta were analyzed in relation to several climatic factors. The basic variables were precipitation, pan evaporation, temperature, hours of sunlight, and wind velocity. The precipitation from April through July was highly correlated with range forage production and this relationship could be utilized to predict the annual forage production by 1 August each year. A slightly better correlation was obtained when range forage production was related to the total of the previous September plus the current April through July precipitation. Pan evaporation totals, mean temperature, and hours of sunlight were negatively correlated with forage production, while wind velocity during the growing season showed a low relationship to forage production. Stepwise regression analysis showed that the inclusion of May and June mean temperatures with June and July precipitation accounted for 63% of the variation in range forage production. The predicted forage yield would be useful in making management decisions or adjustments, especially during drought periods, while the long-term forage yield data can be utilized in range forage models or in validating their effectiveness.
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Infiltration and Sediment Production Following Chemical Control of Sagebrush in New MexicoTerminal infiltration rates under sagebrush canopies were about 35% higher than interspace areas at 3 study sites in northern New Mexico. Differences in infiltration rates among strata may largely be attributed to a greater amount of litter yield and basal cover, and 2 to 3 times higher percentage of organic carbon under the canopy of sagebrush compared to the interspace. Infiltration rates and sediment concentration of runoff within the canopy zone and interspace areas were not affected chemical control treatments. Total sediment production was about 29 to 41% higher under the canopy of tebuthiuron treated sagebrush compared to the canopy zone of untreated rangeland. However, these differences were not consistent and were significant at only 1 study site. Total sediment production was related primarily to a combination of soil texture, sagebrush canopy cover, and total vegetation production.
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Impacts of Black-tailed Jackrabbits at Peak Population Densities on Sagebrush-Steppe VegetationIn the northern Great Basin, populations of black-tailed jackrabbits (Lepus californicus) are cyclic, reaching high densities at approximately 10-year intervals. This project examined impacts of jackrabbits during a peak in their cycle on sagebrush-steppe vegetation in southeastern Idaho. Total vascular plant cover was significantly lower on plots open to jackrabbit herbivory than on exclosure plots, but in no case was cover of a specific species significantly reduced on open plots. The most severe impacts were on shrubs during winter; most aboveground tissues of both winterfat (Ceratoides lanata) and green rabbitbrush (Chrysothamnus viscidiflorus) plants were completely eaten by spring. However, these impacts were largely ameliorated by compensatory growth during the following growing season, and there was no difference in total biomass for either species between the open and protected plots by July. New growth of winterfat plants that had been browsed the previous winter was significantly greater than that of protected plants. Thus, although the cumulative effects of herbivory reduced total plant cover, no single species was irreparably impacted. Over a year, jackrabbits exert feeding pressure on nearly all of the important species in these communities; therefore, these hares do not appear to apply differential grazing pressure that would alter the course of vegetation development on northern Great Basin rangelands.
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Honey Mesquite Control with Pelleted Hexazinone in Western TexasHexazinone [3-cyclohexyl-6-(dimethylamino)-1-methyl-1,3,5-triazine-2,4(1H, 3H)-dione] applied as 1.2 cm3 (20% ai) pellets in a grid pattern at 2.2 kg active ingredient (ai)/ha killed 11 to 22% of undisturbed honey mesquite (Prosopis glandulosa var. glandulosa) 26 months after treatment in experiments at 3 locations in western Texas. Honey mesquite plants <1 m tall were less susceptible to grid pattern applications of hexazinone than were larger plants, probably because the smaller plants lacked sufficient root systems to contact herbicide columns in the soil. Efficacy of hexazinone applied in grid patterns for honey mesquite control increased as soil clay and organic matter contents decreased and as the amount of rock increased. Results from a single experiment indicated that hexazinone pellets applied at 0.8 g ai/plant near the stem base killed 48 to 60% of the honey mesquite plants <2 m in height, but this treatment did not control plants >2 m tall.
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Herbaceous Biomass Dynamics and Net Primary Production Following Chemical Control of Honey MesquiteThe effect of honey mesquite (Prosopis glandulosa var. glandulosa Torr.) control on herbaceous growth dynamics, forage production, and root and crown biomass was investigated in 1979 and 1980 on a site aerially treated with a 1:1 mixture of 2,4,5-T plus picloram at 0.6 kg/ha in May 1974. Density, height, and canopy of honey mesquite trees 5 years after treatment were 248 plants/ha, 0.9 m, and 3.1%, respectively, compared to 963 plants/ha, 2.2 m, and 34.6%, respectively, in the adjacent untreated control plot. Yet, there were no differences between sprayed and untreated plots after 6 and 7 growing seasons relative to species composition, growth dynamics, and production of herbaceous plants. Averaged across years and treatments, estimated aboveground net primary production was 2,525 kg/ha. Crown and root biomass in the top 10 cm of the soil profile averaged 685 and 3,837 kg/ha, respectively, with no significant treatment or year effects. Lack of treatment difference partially validates a conceptual model presently used for economic analysis of herbicide sprays for honey mesquite control. Further, it supports the hypothesis that honey mesquite trees provide critical habitat for the more productive midgrasses indigenous to this site; and that elimination of this habitat in sparse stands of the shrub subsequently limits post-treatment herbage response.
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Growth of Forbs, Shrubs, and Trees on Bentonite Mine Spoil Under Greenhouse ConditionsRevegetation on raw bentonite spoil with or without treatments is often more practical than replacing topsoil in areas where it is scarce or nonexistent. The effect of raw bentonite spoil treated with ponderosa pine sawdust on plant survival and growth was compared to other treatments including perlite, gypsum, straw, vermiculite, and no treatment. Plants tested were the drought- and salt-resistant species of fourwing saltbush (Atriplex canescens (Pursh) Nutt.), rubber rabbitbrush (Chrysothamnus nauseousus (Pallo) Britt.), big sagebrush (Artemisia tridentata tridentata Nutt.), common winterfat (Ceratoides lanata (Pursh) Moq.), Rocky Mountain juniper (Juniperus scopulorum Sarg.), Russian olive (Elaegnus angustifolia L.), common yarrow (Achillea millifolium L.), and desert globemallow (Sphaeralcea ambigua Gray). Desert globemallow, fourwing saltbush, and rubber rabbitbrush had substantial growth and survival on sawdust, perlite, and vermiculite treated spoil. The growth promoting effect of sawdust is particularly promising; it is readily available and cost is minimal.
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Grazing Preferences of Cattle in Regenerating Aspen ForestThe relative preferences of cattle for the major plant species in regenerating aspen (Populus tremuloides) forest following burning were studied to assist in developing strategies for controlling aspen regrowth by grazing with cattle. The tendency of cattle to graze forest rather than grassland increased as grasses matured towards the end of the growing season. Within the forest, cattle preferred herbaceous species when they were present. Of the shrub species, generally wild rose (Rosa spp.) and wild raspberry (Rubus strigosus) were preferred over aspen but aspen was preferred over western snowberry (Symphoricarpos occidentalis). Aspen was grazed more readily late in the season than early. Similarly western snowberry, which was of consistently low acceptability, was relatively more acceptable late in the season. Cattle readily consumed wild raspberry in both years and both seasons. Wild rose was accepted early in the season in both years but was less preferred late in the season when it had relatively more woody growth.
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Gradient Analysis of Vegetation Dominated by Two Subspecies of Big SagebrushStands of vegetation dominated by basin big sagebrush (Artemisia tridentata Nutt. subspecies tridentata) intergrade with stands dominated by Wyoming big sagebrush (Artemisia tridentata Nutt. subspecies wyomingensis) on the Idaho National Engineering Laboratory in southeastern Idaho. Detrended correspondence analysis and correlation were used to elucidate potential relationships between vegetation patterns and soil factors along a gradient from stands having only the subspecies tridentata to stands having only the subspecies wyomingensis. Distributions of the subspecies were consistently associated with gradients in soil texture. Basin big sagebrush was most abundant on sandy soils and Wyoming big sagebrush was dominant on finer textured soils. Mixed stands occurred on central portions of the gradient. Similar results for 3 study areas were observed, despite differences in soil texture between areas. Thus, the distributional patterns are associated with changes in soil texture rather than actual amounts of sand, silt, or clay.
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Germination of Fourwing Saltbush Seeds: Interaction of Temperature, Osmotic Potential, and pHEstablishment of shrubs and other forage plants on arid and semiarid rangelands and salt-contaminated sites may be enhanced if ecotypes with ability to germinate and establish under moisture stress and high temperatures can be identified. The interactive effects of temperature, osmotic potential, and pH on germination were evaluated with seed from 4 populations of fourwing saltbush [Atriplex canescens (Pursh) Nutt.] from western Texas. Predicted optimum temperature (15 to 18 degrees C) from osmotic potential by temperature response surfaces for germination of 3 populations (Valentine, Grandfalls, and San Angelo) were similar to those reported for populations of fourwing saltbush from other western states. Germination of seed collected near Texon, Texas was significantly (P<0.01) affected by media pH range 6 to 9. Seed from the Texon population germinated under lower osmotic potentials compared to the other 3 populations. Total germination of all four populations was enhanced by osmotic potentials lower than 0 MPa. Seed from the Texon population may possess germination characteristics more suitable for arid-land seeding than those from populations near Valentine, Grandfalls, and San Angelo, Texas.
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Forage Utilization Cost Differentials in a Ranch Operation: A Case StudyThe total cost (fee and non-fee) of grazing BLM, FS, and private deeded rangeland was estimated by partial budgeting procedures from records kept by the Saval Ranch, a northeastern Nevada cow-calf operation. Private rangeland was estimated to be the most expensive forage source at $24.99 per AUM. The total cost of grazing BLM land was estimated to be $8.07 per AUM and FS was estimated to cost $9.08 per AUM.
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Flora and Fauna Associated with Prairie Dog Colonies and Adjacent Ungrazed Mixed-grass Prairie in Western South DakotaVegetation, small rodents, and birds were sampled during the growing seasons of 2 years on prairie dog (Cynomys ludovicianus) colonies and adjacent mixed-grass prairie in western South Dakota. Prairie dog grazing decreased mulch cover, maximum height of vegetation, plant species richness, and tended to decrease live plant canopy cover compared to that on ungrazed mixed-grass prairie. Buffalograss (Buchloe dactyloides) was the dominant plant on prairie dog towns and western wheatgrass (Agropyron smithii) and blue grama (Bouteloua gracilis) were most common on mixed-grass prairie sites. Prairie dog towns supported greater densities of small rodents but significantly fewer species compared to undisturbed mixed-grass sites. Deer mice (Peromyscus maniculatus) and northern grasshopper mice (Onychomys leucogaster) were more abundant on prairie dog towns than on undisturbed mixed-grass sites. Density and species richness of birds were significantly greater on prairie dog towns. Horned larks (Eremophila alpestris) were most common on prairie dog towns, whereas western meadowlarks (Sturnella neglecta) were most common on mixed-grass prairie.
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Evaluation of Total Fecal Collection for Measuring Cattle Forage IntakeConventional digestibility trials with steers were conducted to evaluate relationships between actual forage intake and estimated forage intake using the total fecal collection procedure. Actual forage intake of 6 of the 9 forages fed was not accurately estimated by the widely used technique of dividing total fecal output by forage indigestibility estimated by in vitro procedures. This was because 48-h in vitro digestibility poorly estimated in vivo digestibility of 6 forages. Regression equations based on in vivo-in vitro digestibility relationships can reduce but not solve this problem because in vivo processes such as mastication and rumination are bypassed with in vitro techniques. The use of a 36-h microbial digestion period for nongrasses and a 72-96-h microbial digestion period for grasses shows potential to improve in vitro digestibility estimates of cattle in vivo digestibility. Another potential means of improving in vitro digestibility estimates is to select the highest digestibility value from forage or diet samples subjected to 36-, 48-, 60-, 72-, 84- and 96-h microbial digestion periods.
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Estimating Ratios of Live and Dead Plant Material in Clipped PlotsHand separation of live and dead material from clipped plots is tedious and relatively expensive. Live and dead plant materials are easily distinguished under a microscope and can be quickly quantified. After clipping and drying, a sample can be separated in about 10 minutes.
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Effects of N and P Fertilizer Placement on Establishment of Seeded Species on Redistributed Mine TopsoilThe effects of fertilizer on the establishment of seeded grass and legume stands when reclaiming coal strip mines have not been evaluated in northwest Colorado. Nitrogen (0, 28, 56, and 112 kgN/ha) and phosphorus (0 and 56 kgP/ha) were applied in all combinations to the spoils before topsoiling or to the surface after topsoiling. In the greenhouse, herbage yield and yield of roots in the 28 cm of topsoil replaced over the spoil increased as rate of N increased; phosphorus did not increase yield. Nitrogen content of the herbage increased from 1.02% to 1.33% as rate of N increased from 0 to 112 kgN/ha. In a field study in northwest Colorado, neither N nor P fertilizer improved stand establishment ratings. Both the amount and placement of N at time of seeding affected herbage yield during the third growing season. Alfalfa yields were increased 20% by buried P and 44% by surface P in the third growing season. Applying N fertilizer at time of seeding is not recommended.
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Effects of Cattle Grazing on Mule Deer Diet and Area SelectionSplit enclosures, half grazed and half ungrazed by cattle in summer, were compared for mule deer habitat use in late summer using tame deer. Diet composition, dietary nutrition, and area selected for grazing by mule deer were used as criteria to assess the grazing effects of cattle. Generally few dietary or nutritional differences were determined. Nonetheless, deer preferred to forage on areas ungrazed by livestock at low deer use levels, but this preference rapidly decreased as deer use increased.
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Effects of Adenosine Monophosphate on Germination of Forage Species in Salt SolutionsSeed germination can be a limiting step in the establishment of plant species on saline soils. There are indications that the level of adenosine monophosphate (AMP) in the seed may be a limiting factor in seed germination under stress. The objective of this research was to determine if added AMP would improve germination of grass and legume seeds under saline conditions. The seeds of tall fescue (Festuca arundinaceae Schreb. 'K-31'), bluegrama [Bouteloua gracilis (H.B.K.) Lag. ex Steud.], crested wheatgrass [Agropyron cristatum (L) Goertn 'Nordan'], switchgrass (Panicum virgatum L. 'Blackwell'), perennial ryegrass (Lolium perenne L. 'Lynn'), tall wheatgrass [Agropyron elongatum (Host) uv. 'Platte'], Russian wildrye (Elymus junceus Fisch.), western wheatgrass (Agropyron smithii Rydb.), and alfalfa (Medicago sativa L. 'Dawson') were germinated in petri dishes at varying levels of salinity with and without AMP. Time required for germination was shortened for all species, except switchgrass and western wheatgrass, with added AMP. Percent germination of alfalfa was increased with AMP at 14 days in 0.068 M sodium chloride and of tall fescue in the same concentration of sodium sulfate (dibasic). Perennial ryegrass, Russian wildrye and alfalfa demonstrated similar responses at 0.102 M sodium chloride. The germination of alfalfa was improved with AMP at 14 days in 0.034 M sodium sulfate. Adenosine monophosphate tended to have little effect when severe germination depression occurred from high salt concentrations.
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Effect of 20 Years of Low N Rate Pasture Fertilization on Soil AciditySoil acidity resulting from nitrification of ammonium in fertilizer can limit plant growth. In this study on weeping lovegrass (Eragrostis curvula (Schrad.) Nees) and Caucasian bluestem (Bothriochloa caucasica (Trin.) Hubb) pastures on sandy soil in northwestern Oklahoma, 20 years of N fertilization at an average rate of 37 kg N ha-1 yr-1 reduced the pH of the surface 5 cm of soil from 6.7 to 5.3. Sweetclover (Melilotus officinalis (L.) Lam.) and alfalfa (Medicago sativa L.) had symptoms of manganese toxicity when grown in the acidified soil in a glasshouse. The growth of warm-season grasses was not adversely affected when grown in the acidified soil. The lime requirement of the acidified soil was 896 kg CaCO3 ha-1 greater than the lime requirement of adjacent unfertilized pastures. The lime requirements in relation to the amount of acid producing N fertilizer applied was similar to or less than lime requirements reported in the literature for larger N applications to farmlands. Continued use of N fertilizer at low rates will eventually require that once near-neutral soils be limed if species sensitive to acid soil are grown.
