• Tolerance of Kleingrass to Herbicides

      Bovey, R. W.; Baur, J. R.; Bashaw, E. C. (Society for Range Management, 1979-09-01)
      Herbicides propazine, 2,4-D, dicamba, picloram, tebuthiuron, and hexazinone were applied at rates of 0.14 to 2.24 kg/ha pre- and postemergence to greenhouse-grown kleingrass plants. Kleingrass was tolerant to premergence sprays up to and including 1.2 kg/ha of propazine and 0.56 kg/ha of 2,4-D. All other herbicides and rates were phytotoxic to emerging kleingrass. At the early postemergence stage, kleingrass tolerated rates up to and including 0.28, 0.56, and 0.56, and 1.12 kg/ha of picloram, 2,4-D, dicamba, and propazine, respectively; but it did not tolerate tebuthiuron or hexazinone at any rate. At the intermediate vegetative stage (5 to 12.5 cm tall), kleingrass tolerated picloram, 2,4-D, dicamba, and propazine at rates of 0.56, 1.12, and 2.24 kg/ha, respectively, without injury. Mature kleingrass tolerated higher rates of all herbicides than did earlier stages of growth.
    • Safety Modifications for Operations and Transportation of the Rangeland Drill

      Spencer, J. S.; Rashelof, V. M.; Young, J. A. (Society for Range Management, 1979-09-01)
      The drill-arm assemblies of rangeland drills modified to make furrows are difficult and dangerous for one person to raise and secure. A simple modification for safe lifting of these drill arms is described. For transporting rangeland drills on equipment trailers, loading ramps, wheel chocks, and tie-downs were developed and tested. All of these modifications make the use of rangeland drills safer and easier.
    • Renovation of Sparse Stands of Crested Wheatgrass

      Eckert, R. E. (Society for Range Management, 1979-09-01)
      Atrazine at 0.56 kg/ha and simazine at 1.12 kg/ha were evaluated for renovating sparse stands (0.9 to 1.5 m between plants) of resident crested wheatgrass. The study was repeated for 3 years for both weed control and seeding of crested wheatgrass. Both herbicides reduced yield and reproductive potential of downy brome and tumble mustard in the fallow year. Neither herbicide significantly damaged the vegetative or reproductive parts of resident crested wheatgrass plants. Atrazine residues in the soil in the fall of the fallow year and spring of the seeding year were below the toxic level for crested wheatgrass seedling. Simazine residues were above the toxic level. Both herbicides increased seed production of resident crested wheatgrass plants and neither adversely affected seed test weight and germination, or root and shoot growth of seedlings from seed of these plants. Weed competition during the seedling year was reduced by herbicide treatment. Density of crested wheatgrass seedlings and established plants was greatest on treated plots in 2 of 3 years. Based on low triazine residues and increased crude protein, resident crested wheatgrass on treated areas would be excellent forage during the fallow year. High levels of NO3- N, trans-aconitate, and K, but low Mg suggest that grass tetany could be a problem if lush herbage on treated areas was grazed during the spring period.
    • Relative Annual Broomweed Abundance as Related to Selected Climatic Factors

      Heitschmidt, R. K. (Society for Range Management, 1979-09-01)
      Regression models were developed to predict relative abundance of annual broomweeds on a Texas rangeland as a function of selected climatic factors. Based on 16 years' data, above-average precipitation in May and below-average daily maximum temperatures in April were the principal climatic factors most closely associated with heavy infestations of annual broomweeds for any given year (R2 = 0.902). Similar models developed from bimonthly and trimonthly averages were less precise than monthly averages for predicting relative abundance of annual broomweed.
    • Range Rehabilitation Enhances Cotton Rats in South Texas

      Guthery, F. S.; Anderson, T. E.; Lehmann, V. W. (Society for Range Management, 1979-09-01)
      During August 1961 in Kleberg County, Texas, cotton rat density was four times greater on areas planted to exotic grasses than on native rangeland, and density was six times greater on rootplowed areas. A regression model using standing crop biomass of herbaceous vegetation and percentage composition of standing crop furnished by sida, bristlegrasses, and sumpweed plus ragweed explained 81.4% of the variation in cotton rat density.
    • Range Fertilization: Plant Response and Water Use

      Wight, J. R.; Black, A. L. (Society for Range Management, 1979-09-01)
      During the 10-year study, herbage production on an unfertilized, mixed prairie range site in eastern Montana averaged 1,047 kg/ha and ranged from 720 to 1,321 kg/ha. Elimination of nitrogen (N) and phosphorus (P) deficiencies by fertilizing increased herbage yields an average of 114% (ranging from a low of 32% in a "dry" year to a high of 218% in a "wet" year). Nitrogen was the major growth-limiting plant nutrient with measurable responses to P occurring only when N was nonlimiting. Single high-rate applications were about equal to annual N applications when compared on an annual rate equivalent basis. Species composition varied as much among years as among fertilizer treatments. At N rates of 336 kg/ha or less, cool-season grasses increased in about the same proportion as did forbs and shrubs, maintaining a relatively constant composition of the major species groups. On unfertilized plots, herbage yields and water use reached maximum values of about 1,250 kg/ha and 265 mm, respectively, regardless of further increases in available water. Unfertilized plots produced an average of 2.60 kg/ha for each 1 mm of precipitation received as compared with 5.81 kg/ha on fertilized plots.
    • Range Fertilization: Nitrogen and Phosphorus Uptake and Recovery Over Time

      Black, A. L.; Wight, J. R. (Society for Range Management, 1979-09-01)
      Little information has been published concerning the long-term effects of N and P fertilization on nutrient cycling and availability of N and P as related to quantity and quality of native grassland herbage. Factorial combinations of ammonium nitrate at rates of 0, 112, 336, and 1,008 kg N/ha and concentrated superphosphate at rates of 0, 112, and 224 kg P/ha were broadcast once in the spring of 1969 on a native range site (Bouteloua-Carex [Stipa] faciation of a mixed prairie association). During the next 8-years, plant N and P content of grasses and nongrasses increased for periods of time proportionated to the rate of N and P applied. Plant N content tended to be low in "wet" years and relatively high in "dry" years. Conversely, plant P content ended to be high in "wet" years and relatively low in "dry" years. After the first 2 years, the increase in plant N and P uptake, resulting from a given level of N-P fertilization, continued at a rather stable rate as compared with the unfertilized check. In 1973, the unfertilized check had 20,700 kg/ha of root material in the upper 30 cm of soil. The fertilized (336 kg N/ha plus 224 kg P/ha) grassland had 24,310 kg/ha of root material which contained 116 kg/ha more N and 8 kg/ha more P than did the check. Therefore, the below-ground root system is a nutrient-deficient sink which has a high potential to immobilize relatively large quantities of applied N and P fertilizer materials. This study revealed the long-term benefits of N and P fertilization on forage quality which may persist for several years after yield responses are no longer apparent.
    • Invasion of Imperata cylindrica (L.) Beauv. by Eupatorium Species in Northern Thailand

      Falvey, J. L.; Hengmichai, P. (Society for Range Management, 1979-09-01)
      The pattern of invasion of native Imperata cylindrica swards by Eupatorium in the highlands of northern Thailand was studied by the technique of comparing invasion at different sites of known history. Eupatorium ground cover decreased with increasing distance from the night camp of cattle. Variations in the curves between different villages was attributed to the number of years of sustained grazing each site had undergone. A more detailed study of one area showed a high correlation (r=0.887) between mean percent Eupatorium and the number of years of grazing, but not for estimated average stocking rate at each site. The correlation coefficient between percent Eupatorium and the product of the number of years grazing and estimated average stocking rate at each site was also high (r=0.894). Some agronomic data for E. adenophorum in one area are also presented.
    • Interference of Sand Sagebrush Canopy with Needleandthread

      Davis, J. H.; Bonham, C. D. (Society for Range Management, 1979-09-01)
      The influence of sand sagebrush (Artemisia filifolia) on the biomass of several components of needleandthread (Stipa comata) was studied on grazed and ungrazed sites in eastern Colorado. The components examined were seeds, stems-leaves combined, crowns, and total plant biomass. A significant grazing × association interaction was observed in terms of seed biomass and stem-leaf combined biomass. Sagebrush afforded protection for needleandthread from grazing, which outweighed the effects of interference on grazed sites. In contrast, on the ungrazed site needleandthread biomass was greater in the open than underneath the sage. These results imply that a comparison of yield in pure and mixed stands on grazed sites are not valid for measuring interference effects between shrubs and grasses. The advantage of measuring several plant components in competition studies was also discussed.
    • Improvement of Gulf Cordgrass Range with Burning or Shredding

      McAtee, J. W.; Scifres, C. J.; Drawe, D. L. (Society for Range Management, 1979-09-01)
      Shredding or burning during the spring, summer, or winter increased the live gulf cordgrass standing crop, decreased the dead gulf cordgrass standing crop, and increased the percentage of plants supporting inflorescences by the end of the first growing season after treatment on a clay site. The most favorable growth responses resulted from treatment in the spring, apparently because subsequent rainfall was greater than following summer treatments. Shredding generally stimulated herbaceous yields more than burning. Presumably the heavy mulch cover after shredding improved moisture relationships relative to the bare surface following fires. Burning or shredding resulted in less favorable responses on a saline fine sand than on the clay site. However, on the saline fine sand as on the clay site, shredding promoted production of gulf cordgrass more than did burning. Both methods are effective for improving gulf cordgrass range for livestock grazing, but burning is apparently the more economical alternative.
    • Impacts of Off-Road Vehicles on Infiltration and Sediment Production of Two Desert Soils

      Eckert, R. E.; Wood, M. K.; Blackburn, W. H.; Peterson, F. F. (Society for Range Management, 1979-09-01)
      Impacts of motorcycle and 4-wheel drive truck traffic on infiltration rate and sediment production were evaluated on two desert soils. Infiltration was similar for both soils; however, more sediment was produced from a surface with exposed mineral soil than from a gravel-mulched surface. Infiltration was 3 to 13 times greater on the coppice soil beneath shrubs than on interspace soil between shrubs, but sedimentation was 10 to 20 times greater on interspace soil. Infiltration was less and sediment yield was greater after soil was disturbed by vehicular traffic, and after reformation of the surface crust, particularly on interspace soil. High sediment production from interspace soil was attributed to reduced infiltration after 10 minutes. The soil then became saturated and unstable, was dispersed by raindrop impact, and particles were carried in runoff water for the remaining 20 minutes of the test period. Coppice soil had a high infiltration rate for the entire test period and did not become saturated. In addition, the high organic matter and aggregate stability of coppice soil prevented soil movement, though some runoff occurred.
    • Herbage Yield and Nitrate Concentration in Meadow Plants as Affected by Environmental Variables

      Gomm, F. B. (Society for Range Management, 1979-09-01)
      Livestock losses from NO3 poisoning vary among locations. An understanding of the effect of environmental factors on NO3 accumulation in meadow plants may aid in management of meadowlands to reduce these losses. Controlled studies were undertaken to determine the effect of soil moisture, temperature, irradiance, and soil fertility on the yield and NO3 concentrations in herbage tissue of slender sedge (Carex praegracilis W. Boott), beardless wildrye (Elymus triticoides Buckl.), Nevada bluegrass (Poa nevadensis Vasey ex Scribn.) and reed canarygrass (Phalaris arundinacea L.). Reed canarygrass consistently yielded higher and contained higher concentrations of NO3 than the other species. Herbage yields were higher in all plants grown for 45 days at 30 degrees C than in those grown for 45 days at 15 degrees C. Yields were also higher in plants grown with 42.0 W/ m2 than they were in plants grown with 4.2 W/ m2. Concentrations of NO3 were highest when plants were grown in unsaturated soil, with 4.2 W/ m2, and they increased with fertilization. The NO3 concentrations obtained could be toxic to cattle (lethal NO3- N level = 0.21%), especially when the plants were grown at 30°C in dry soils. When meadow plants were grown in saturated soil, the NO3 concentrations were never high enough to be toxic, even when the plants were heavily fertilized.
    • Forage Yield, Phenological Development, and Forage Quality of an Agropyron Repens x Agropyron spicatum Hybrid

      Perez-Trejo, F.; Dwyer, D. D.; Asay, K. H. (Society for Range Management, 1979-09-01)
      Studies were conducted to evaluate the potential of the Agropyron repens (L.) Beauv. × Agropyron spicatum (Pursh) Scrib. & Smith hybrid as a forage grass. The hybrid was compared with its parental species for phenological development, chemical composition, in vitro dry matter digestibility, and acceptance by sheep. The new species was highly productive, maintained a high nutritional value, especially in its fall regrowth, and was readily accepted by sheep. In most respects it was intermediate to its two parents. Results of these studies indicate the hybrid has potential as a forage species under certain rangeland conditions.
    • Foods of Primary Consumers on Cold Desert Shrub-Steppe of Southcentral Idaho

      Johnson, M. K. (Society for Range Management, 1979-09-01)
      Trophic relationships of rabbits, black-tailed jack rabbits, pronghorn, sheep, and cattle were examined on the Idaho National Engineering Laboratory Site in southcentral Idaho. Grasses were the most important foods of lagomorphs and livestock. Pronghorn depended mostly on basin big sagebrush, common winterfat, and saltbushes. If jack rabbits increase in the future, severe competition for forage with livestock may result.
    • Digestible Energy and Protein Content of Gulf Cordgrass following Burning or Shredding

      McAtee, J. W.; Scifres, C. J.; Drawe, D. L. (Society for Range Management, 1979-09-01)
      Digestible energy and crude protein content of green gulf cordgrass forage was significantly increased for 30 to 90 days after burning or shredding on the Coastal Prairie. Within 30 days after treatment, digestible energy content ranged from 2,414 to 2,891 kcal/kg in regrowth on burned areas, and from 1,879 to 2,602 kcal/kg on shredded areas compared to 1,612 to 1,917 kcal/kg in green leaves of plants from untreated areas. Crude protein content at the same time was 9 to 11% following burning or shredding compared to 4 to 5% in green plant material from untreated areas. Differences in the nutritional components varied more with time after sampling within a season of treatment when they varied among seasons of treatment or between methods of treatment. Therefore, both burning and shredding have potential for increasing nutritional value of gulf cordgrass during the cool season, a period when other green forages are scarce on the Coastal Prairie.
    • Differentiation of Serviceberry Habitats in the Wasatch Mountains of Utah

      Yake, S.; Brotherson, J. D. (Society for Range Management, 1979-09-01)
      Utah serviceberry (Amelanchier utahensis Koehne) and its habitats were studied in the Wasatch Mountains of central Utah. Twenty-five populations were selected and sampled for various biotic and abiotic environmental variables. Regression, correlation, cluster, and discriminant analyses were used to analyze the data. Sites of northern exposure exhibited a more luxuriant vegetation than southern exposures. Although all the study sites contained Utah serviceberry as a dominant or subdominant plant, they can be classified into three major habitat types according to associated dominants and/or geographical location. These groups are serviceberry-dominated foothill knolls; oak-serviceberry-dominated northern exposures; and serviceberry-dominated southerly exposures. Analyses demonstrated overlap between the major selected habitat types. The most distinct habitat was the foothill knolls; the least distinct was the southern exposed serviceberry habitat. The serviceberry habitat on southerly exposures is environmentally intermediate between the foothill knolls and higher elevation northern exposed sites on which serviceberry shares dominance with oak. Discriminant analysis indicated that pH, slope, sand, soluble salts, and clay were the environmental factors most important in distinguishing between the major habitat types.
    • Differential Response of Subalpine Meadow Vegetation to Snow Augmentation

      Knight, D. H.; Weaver, S. W.; Starr, C. R.; Romme, W. H. (Society for Range Management, 1979-09-01)
      Experimental results from two subalpine meadows in Wyoming suggest that prolonged snow cover due to winter cloud seeding could increase the productivity of dry meadows while causing a decline in the productivity of mesic meadows. Shifts in species composition may also occur. Though statistically significant, the observed effects were subtle and would be expected primarily in areas where larger snow drifts could develop.
    • Creeping Bluestem Response to Prescribed Burning and Grazing in South Florida

      White, L. D.; Terry, W. S. (Society for Range Management, 1979-09-01)
      Many research studies have developed guidelines for managing wiregrass ranges to improve utilization of relatively unpalatable Aristida and Sporobolus spp. This traditional management has generally produced low livestock returns. Recent management trends have been toward the promotion and utilization of more desirable bluestems, paspalums, panicums, etc. This study was initiated to determine how wiregrass management affects excellent creeping bluestem pastures. Results indicate that prescribed burning stimulated reproductive clum development at the expense of foliage production. Grazing of burned areas with dominance of reproductive culms resulted in a substantial decrease in creeping bluestem tiller survival and herbage production. Continuous grazing of burned areas allows the more grazing resistant wiregrasses and shrubs to increase and probably accounts for the present expanse of wiregrass ranges. Deferment of grazing until seedset of desirable grasses following late winter burning would promote the development of productive bluestem pastures. Prescribed burning is a recommended practice to be continued for south Florida; however, it should occur after cattle have been removed from the pasture. A rotation system with fire every 3 to 5 years is suggested to improve ranges from wiregrass to bluestem dominance and to maintain creeping bluestem pastures.
    • Cattle Diets on a Fertilized Blue Grama Upland Range Site

      Havstad, K.; Pieper, R. D.; Donart, G. B.; Wallace, J. D.; Cordova, F. J.; Parker, E. E. (Society for Range Management, 1979-09-01)
      Botanical composition of cattle diets was similar for cattle grazing a nitrogen- fertilized and unfertilized upland range site. Sand dropseed and blue grama were the major dietary components on both fertilized and unfertilized treatments. Fertilization did not influence the content of these two species in the diet. Galleta made up a larger portion of the diet on the unfertilized pasture than on the fertilized pasture during the spring and had a higher preference index on the unfertilized pasture. Scarlet globe-mallow comprised a greater proportion of the diet of cattle grazing on the fertilized pasture than for those grazing on the unfertilized pasture during the summer. Diversity indices indicated that diets of cattle grazing the unfertilized pasture were more diverse than those of cattle grazing on the fertilized pasture.