• Cane Bluestems: Forage Yield, Forage Quality, and Water-Use Efficiency

      Koshi, P. T.; Eck, H. V.; Stubbendieck, J.; McCully, W. G. (Society for Range Management, 1977-05-01)
      Three collections of cane bluestem (Bothriochloa barbinodis Herter) were evaluated under three water and three harvest regimes. Dry matter yields, under natural rainfall and irrigation, averaged 3.8 and 8.7 metric tons/ha, respectively. Productivity of the three collections ranked G-866 > G-820 > PMT-333 under natural rainfall, but with irrigation, the ranking was G-820 > G-866 > PMT-333. One and two harvests per season resulted in near-equal yields, but three harvests decreased yields. Cane-bluestem forage contained about 10% protein and 0.22% phosphorus (P) in mid-June. In November, previously unclipped forage contained 4.4% protein and 0.12% P, while that clipped twice contained 7.3% protein and 0.18% P. Yield and quality of cane bluestem compared favorably with that of switchgrass (Panicum virgatum L.) grown in a similar study. Maximum production was obtained with about 77 cm of water use (rainfall + irrigation + soil water).
    • Canopy analysis as a technique to characterize defoliation intensity on Sandhills range

      Miller-Goodman, M. S.; Moser, L. E.; Waller, S. S.; Brummer, J. E.; Reece, P. E. (Society for Range Management, 1999-07-01)
      Characterization of relationships between grazing and vegetation responses is difficult. Rapid and accurate measurement of pasture canopy characteristics would help clarify these relationships if canopy changes are directly related to grazing variables. The objectives of this study were (1) to evaluate use of the LI-COR LAI-2000 for quantification of changes in canopy density and architecture in response to defoliation by cattle, (2) to determine if changes in leaf area index (LAI) measured with the LAI-2000 are related to stocking rate, and (3) to determine advantages and drawbacks of the LAI-2000 for monitoring grazing impacts on canopy density and architecture. Leaf area index and mean foliage tilt angle were measured before and after defoliation by cattle (Bos taurus L.) in June, July, and August under 9 grazing treatments on Nebraska Sandhills range. Differences in LAI could be attributed to certain grazing treatments at various points throughout the season. Grazing treatment had little impact on mean foliage tilt angle. Change in LAI (delta LAI) had a significant negative relationship with stocking rate (P < or = 0.0001). The relationship detected for delta LAI versus stocking rate predicted LAI reductions of between 0.14 and 0.40 for the range of stocking rates studied; stocking rate accounted for 62% of the decrease in LAI caused by grazing. When configured for the Sandhills canopy, the LAI-2000 provided a rapid and precise method for quantification of the degree of defoliation associated with grazing.
    • Canopy Area and Aboveground Mass of Individual Redberry Juniper (Juniperus pinchotii) Trees

      Ansley, R. J.; Mirik, M.; Surber, B. W.; Park, S. C. (Society for Range Management, 2012-03-01)
      There is increasing interest in using canopy area to quantify biomass of invasive woody plants on large land areas of rangelands for a variety of reasons. For those woody species that emphasize lateral canopy growth over vertical growth it may be possible to relate canopy area to aboveground mass (AGM). Our objective was to determine the utility of external canopy measurements (area, volume, and height) for predicting AGM and the percentage of AGM that is wood (PW; i.e., stems >3 cm diameter) in individual redberry juniper (Juniperus pinchotii Sudw.) plants in west Texas. The canopy area to height relationship was curvilinear and indicated that at heights >3 m, there was more lateral (canopy area) than vertical canopy growth. We found a strong linear relationship between canopy area and AGM (r2 = 0.94; AGM range 9 kg to 688 kg) and it appeared that AGM could be predicted in individual trees from canopy area. Moreover, the canopy area/AGM relationship developed from smaller trees was able to adequately predict AGM of larger trees. Height was a less effective predictor of AGM (r2 = 0.66), and incorporation of height with canopy area to determine canopy volume did little to improve accuracy of estimating AGM over canopy area alone. The canopy area/PW relationship was curvilinear (the rate of increase in Pw declined in larger trees) and PW reached 60-70% in the largest trees./Aumenta el interés por usar el área del dosel para cuantificar la biomasa de plantas leñosas invasoras en grandes extensiones de pastizales por diversas razones. Para esas especies leñosas que resaltan el crecimiento lateral del dosel lateral sobre el crecimiento vertical puede ser posible relacionar el área de dosel con la biomasa aérea (BA). Nuestro objetivo fue determinar la utilidad de medir el dosel externo (área, volumen y altura) para predecir BA y el porcentaje de BA que es madera (PW, ejemplo tallos >3 cm de diámetro) en plantas individuales de junípero rojo (Juniperus pinchotii Sudw.) en el oeste de Texas. El área del dosel con la relación de altura fue curvilínea e indicaba que la altura >3 m fue más lateral (área del dosel) que el crecimiento vertical del dosel. Encontramos una fuerte relación linear entre el área del dosel y BA (r2=0.94; BA rango 9 kg a 688 kg) y esto parece que BA puede ser predicha en arboles individuales de área del dosel. Sin embargo, la relación área del dosel/BA desarrollada de arboles pequen ̃os fue posible predecir adecuadamente BA de arboles grandes. Altura del árbol fue un factor de predicción menos efectivo de BA(r2=0.66), al incorporar altura con área del dosel para determinar el volumen del dosel mejoro muy poco la exactitud la estimación de BA sobre el área del dosel por sí solo. La relación de área del dosel/madera (PW) fue curvilínea (la tasa de incremento de madera (PW) declino en arboles grandes) y la madera (PW) alcanzo 60–70% en arboles grandes.
    • Canopy Cover as a Method of Monitoring Trend in Ecological and Soil Status

      Anderson, E. William (Society for Range Management, 1988-02-01)
    • Canopy Reflectance and Film Image Relations among Three South Texas Rangeland Plants

      Gausman, H. W.; Everitt, J. H.; Gerbermann, A. H.; Bowen, R. L. (Society for Range Management, 1977-11-01)
      Field spectroradiometric measurements for canopy reflectances of three dominant south Texas woody plants (cenizo, honey mesquite, live oak) were used successfully to predict their color infrared film images and distinguishability: cenizo, whitish; honey mesquite, relatively light magenta; and live oak, darker magenta.
    • Canopy spectra of giant reed and associated vegetation

      Everitt, J. H.; Yang, C.; Alaniz, M. A.; Davis, M. R.; Nibling, F. L.; Deloach, C. J. (Society for Range Management, 2004-09-01)
      This paper describes the spectral light reflectance characteristics of giant reed (Arundo donax L.) and the application of aerial color-infrared photography and videography for distinguishing infestations of this invasive plant species in Texas riparian areas. Airborne videography was integrated with global positioning system (GPS) and geographic information system (GIS) technologies for mapping the distribution of giant reed. Field spectral measurements showed that giant reed had higher near-infrared reflectance than associated plant species in summer and fall. Giant reed had a conspicuous pink image response on the color-infrared photography and videography. This allowed infestations to be quantified using computer analysis of the photographic and videographic images. Accuracy assessments performed on the classified images had user's and producer's accuracies for giant reed that ranged from 78% to 100%. Integration of the GPS with the video imagery permitted latitude-longitude coordinates of giant reed infestations to be recorded on each image. A long stretch of the Rio Grande in southwest and west Texas was flown with the photographic and video systems to detect giant reed infestations. The GPS coordinates on the color-infrared video scenes depicting giant reed infestations were entered into a GIS to map the distribution of this invasive weed along the Rio Grande.
    • Canopy Structure of a Tall-grass Prairie

      Conant, S.; Risser, P. G. (Society for Range Management, 1974-07-01)
      Several characteristics of vegetation structure, including height, basal cover, cover repetition, leaf area, and distribution of aboveground biomass, were examined in grazed and ungrazed treatments of native Oklahoma tall-grass prairie. Selected structural parameters were evaluated to determine their value as reliable predictors of biomass dynamics. Cover repetition and leaf area showed good correlation with above-ground biomass. Studies of vegetation structure may provide an additional basis for understanding grazing response in grassland communities, and may serve as a basic tool for clarifying the roles of water, light and nutrients, and their effects on grassland production.
    • Carbohydrate and Nitrogen Reserve Cycles for Continuous, Season-long and Intensive-early Stocked Flint Hills Bluestem Range

      Owensby, C. E.; Smith, E. F.; Rains, J. R. (Society for Range Management, 1977-07-01)
      Effects of intensive, early stocking (twice the normal stocking rate from May 1 to July 15) and continuous, season-long stocking from May 1 to October 1 with yearling steers on big bluestem carbohydrate and reserve cycles were studied 3 years in the Kansas Flint Hills. Big bluestem reserve carbohydrates were similar during the dormant season under both stocking systems, but lower on the intensive-early stocked pasture during mid-summer than on the continuous, season-long stocked one. By growing season's end carbohydrate reserves were similar for both stocking systems. Stocking system did not affect the nitrogen reserve cycle. Big bluestem vigor and regrowth potential were similar for both systems.
    • Carbohydrate and Organic Nitrogen Concentrations within Range Grass Parts at Maturity

      Perry, L. J.; Moser, L. E. (Society for Range Management, 1974-07-01)
      Total nonstructural carbohydrate (TNC) levels were significantly different among eight range grasses at maturity. Roots, rhizomes, and stem bases (storage organs), differed significantly in percentage TNC within rhizomatous and bunch-type (non-rhizomatous) grasses. Percent organic nitrogen differed significantly among grasses and storage organs but not to the same extent as occurred with TNC. We suggest that TNC concentrations of storage organs must be determined for each grass before sampling for TNC levels, in order to locate storage organs with greatest TNC concentration.
    • Carbohydrate Concentrations in Honey Mesquite Roots in Relation to Phenological Development and Reproductive Condition

      Wilson, R. T.; Dahl, B. E.; Krieg, D. R. (Society for Range Management, 1975-07-01)
      Lower concentrations of total available carbohydrates were found throughout the growing season in roots of honey mesquite trees with many flowers and pods than in trees with a low reproductive potential. Following bud burst, during the period of pod elongation, mesquite trees with few reproductive organs replenished the root issue with carbohydrates faster than did trees bearing many reproductive organs. During the seed development phase of growth, a second decline in root carbohydrate concentrations occurred. This decline began approximately 1 week later in the heavily fruited trees compared to the trees with few pods. Variation in carbohydrate storage among trees differing in reproductive potential largely explains why it is difficult to consistently kill mesquite roots with growth regulating herbicides. When carbohydrates are no longer accumulating in the roots of trees with few flowers or seed pods, those trees with many reproductive organs may be accumulating carbohydrates. Since herbicides such as 2,4,5-T move to the roots when carbohydrates are accumulating, little herbicide would get to the roots in the one case. Optimum herbicide application dates for West Texas would generally occur from May 15 to June 15 and from July 1 to July 15.
    • Carbohydrate Content of Underground Parts of Grasses As Affected by Clipping

      Kinsinger, F. E.; Hopkins, H. H. (Society for Range Management, 1961-01-01)
    • Carbohydrate Levels and Control of Blackjack Oak and Winged Elm Treated with Tebuthiuron and 2,4,5-T

      Shroyer, J. P.; Stritzke, J. F.; Croy, L. I. (Society for Range Management, 1979-01-01)
      The effects of tebuthiuron N-[5(1,1-dimethylethyl)-1,3,4-triadiazol-2-yl]-N,N′ dimethylurea) and 2,4,5-T[(2,4,5-trichlorophenoxy) acetic acid] on total nonstructural carbohydrates (TNC) in the roots of blackjack oak (Quercus marilandica Muench.) and winged elm (Ulmus alata Michx) were evaluated. Tebuthiuron was applied to the soil in February 1976 at 2.24 kg/ha and 2,4,5-T was foliar applied at 2.24 kg/ha in May 1976. Tree kill 1 year after treatment with tebuthiuron was 100% for both woody species. No tree kill resulted from treatment with 2,4,5-T, and canopy reduction after 1 year was 50 and 70% for winged elm and blackjack oak, respectively. The TNC content of both winged elm and blackjack oak roots was significantly reduced following application of 2,4,5-T and tebuthiuron. The TNC content of roots from trees growing in tebuthiuron-treated areas did not significantly increase after treatment (TNC contents of 6 and 7%, respectively for blackjack oak and winged elm on October 13). There was some increase in TNC content of roots from trees sprayed with 2,4,5-T, and by October the TNC content in blackjack oak and winged elm roots was 10 and 19%, respectively. This compared to TNC contents of 36 and 32%, respectively for untreated blackjack oak and winged elm.
    • Carbohydrate Reserve Content of Mountain Range Plants Following Defoliation and Regrowth

      Donart, G. B.; Cook, C. W. (Society for Range Management, 1970-01-01)
      Following the establishment of a curve for carbohydrate reserve levels in the roots of six native range plants in relation to phenological development, the effect of heavy clipping at the time of carbohydrate low and carbohydrate high was studied. The carbohydrate reserves in all species except senecio were significantly affected by defoliation treatment. Results indicated that defoliation of grasses and forbs early in the season was more detrimental than defoliation late in the season, but defoliation of browse late in the season appeared to lower reserves more than early defoliation.
    • Carbohydrate Reserve, Phenology, and Growth Cycles of Nine Colorado Range Species

      Menke, J. W.; Trlica, M. J. (Society for Range Management, 1981-07-01)
      Nine Colorado range species were studied for two consecutive years to relate the carbohydrate reserve status with phenological stage of development and current annual growth, including leaf, twig, or seedstalk length, or plant height. The species were four-wing saltbush (Atriplex canescens), antelope bitterbrush (Purshia tridentata), little rabbitbrush (Chrysothamnus vicidiflorus), fringed sagewort (Artemisia frigida), scarlet globemallow (Sphaeralcea coccinea), blue grama (Bouteloua gracilis), western wheatgrass (Agropyron smithii), James' cryptantha (Cryptantha jamesii), and pricklypear cactus (Opuntia polyacantha and rhodantha in a mixed stand). Seasonal total nonstructural carbohydrate (TNC) reserve cycles were related to phenological stages of development. Growth of all species appeared to be stimulated by late-summer or fall precipitation. Growth was found to be related inversely to carbohydrate reserve storage. Fourwing saltbush and antelope bitterbrush had typical V-shaped annual carbohydrate reserve cycles, and little rabbitbrush had a somewhat flat or extended V-shaped cycle. Fringed sagewort, scarlet globemallow, and western wheatgrass had flat or extended V-shaped cycles and maintained low reserves for more of the growing season than any of the species with typical reserve cycles. Blue grama was the only species that exhibited a narrow V-shaped cycle. The shape of the seasonal TNC cycle appeared to be a good screening tool for assessing the relative effects of defoliation on different plant species. Plants that replenished reserves rapidly after spring draw-down and regrowth periods, and minimized the part of the growing season with low reserve status, were least affected by defoliation and recovered rapidly from severe defoliation.
    • Carbohydrate Reserves in Roots of Sand Shin Oak in West Texas

      Bóo, R. M.; Pettit, R. D. (Society for Range Management, 1975-11-01)
      Total nonstructural carbohydrate (TNC) concentrations in the root system of sand shin oak (Quercus havardii) were analyzed from January, 1972, through December, 1973. Effects of shredding on root reserves were also explored. In both years root TNC varied with the different phenological growth stages. Reserves were gradually depleted throughout the dormant season, November to April, until the low of 6.5 and 7.0% was reached in early May of 1972 and 1973, respectively. TNC then began to accumulate in the roots when the leaves were from 1/3 to 1/2 full size. Shredding significantly reduced root reserves for 6 months. Early leaf expansion is a good indicator of downward carbohydrate translocation and may be the best guideline available for the application of systemic herbicides to effect oak control.
    • Carbohydrate Reserves of Crested Wheatgrass and Russian Wildrye as Influenced by Development and Defoliation

      Trlica, M. J.; Cook, C. W. (Society for Range Management, 1972-11-01)
      Carbohydrate reserves of crested wheatgrass (Agropyron cristatum) and Russian wildrye (Elymus junceus) were lowest after initial spring growth, but maximum levels were rapidly attained as plants approached maturity. Fall regrowth caused reductions in total available carbohydrate (TAC) stores. More TAC reserves were used to produce new growth if plants were defoliated during spring growth than if defoliated at maturity or quiescence. Autumn TAC storage levels in both crested wheatgrass and Russian wildrye were reduced by all previous defoliations. Autumn reserve storage was directly related to the amount of new growth produced after defoliation. Results indicate that both crested wheatgrass and Russian wildrye are adapted for either fall or early spring grazing and under some circumstances for spring-fall use. Defoliation when plants are rapidly replenishing reserves or before maturity reduces subsequent new growth and carbohydrate reserve stores in the autumn.
    • Carbohydrate Reserves of Grasses: A Review

      White, L. M. (Society for Range Management, 1973-01-01)
      Carbohydrate reserves are nonstructural carbohydrates. Sucrose and fructosan are the predominant reserve constituents of temperate-origin grasses; sucrose and starch, of tropical-origin grasses. Nitrogenous compounds are used in respiration, but probably are not alternately stored and utilized as are carbohydrate reserves. Most carbohydrate reserves are stored in the lower regions of the stems-stem bases, stolons, corms, and rhizomes. Nonstructural carbohydrates in the roots of grasses are probably not used directly in herbage regrowth following herbage removal. Plant development stage, temperature, water stress, and nitrogen fertilization can drastically change the reserve level. The seasonal variation of carbohydrate reserves is often different for the same species when grown in different environments. The level of carbohydrate reserves in the lower regions of the stems apparently affects the regrowth rate for the first 2 to 7 days following herbage removal. Following the initial period, plant regrowth rate depends on other factors, such as leaf area and nutrient uptake. This initial effect from the level of carbohydrate reserves can be maintained during subsequent exponential growth. Grazing may be more detrimental than clipping if it removes herbage from some plants and not others. The ungrazed plants may take the available nutrients and water away from the grazed plants. However, grazing may be less detrimental than clipping if grazing leaves ungrazed tillers on a plant while removing others, thus allowing for the transfer of carbohydrates.
    • Carbohydrate Reserves of Intermediate Wheatgrass after Clipping and Etiolation Treatments

      Ogden, P. R.; Loomis, W. E. (Society for Range Management, 1972-01-01)
      The total water-soluble carbohydrate (TWSC) fraction of intermediate wheatgrass stem bases and roots is depleted with etiolation and is a good measure of the reserve energy of this species. When the TWSC fraction was depleted to about 1% dry weight, vigor of the grass was too poor to recover from a clipping treatment. Root weight was also reduced with etiolation. Late September to early November was a period of active herbage and root growth for intermediate wheatgrass. Growth during this fall period enabled grasses which had been clipped three times at 6-week intervals during the summer to recover to very nearly the level of TWSC and root weight as the check plants.
    • Carbohydrate Reserves of Sand Reedgrass under Different Grazing Intensities

      Welch, T. G. (Society for Range Management, 1968-07-01)
      Stored carbohydrates of sand reedgrass increased from a low in late May and early June to a maximum in late September and early October. Starch was the major stored carbohydrate. The concentration of starch in the roots decreased slightly with increased grazing intensity. The results of this study combined with information on the morphological development, extent of root system, and other physiological aspects of sand reedgrass can be used in developing grazing management systems for sand reedgrass.
    • Carbohydrate Reserves of Six Mountain Range Plants as Related to Growth

      Donart, G. B. (Society for Range Management, 1969-11-01)
      The total available carbohydrate reserves of six native mountain range plants were studied through a growing cycle. The reserves showed somewhat similar trends as plants advanced in growth during their annual cycle. Minimum root reserves were reached during the early spring after producing approximately 15 percent of their annual growth. Maximum reserves were reached at or near flowering. The average level of root reserves at any one period varied widely among species, however.