• Determination of root mass ratios in alfalfa-grass mixtures using near infrared reflectance spectroscopy

      Rumbaugh, M. D.; Clark, D. H.; Pendery, B. M. (Society for Range Management, 1988-11-01)
      Hand separation of roots of 2 or more plants species from soil cores is a tedious and labor-intensive task. Our objective was to determine whether near-infrared reflectance spectroscopy (NIRS) could be employed to estimate root biomass proportions in binary mixtures of alfalfa (Medicago sativa L.) with each of 4 grasses. Grasses chosen for experimentation were crested wheatgrass (Agropyron cristatum L.), intermediate wheatgrass [Thinopyrum intermedium (Host) Barkworth & D.R. Dewey], an intergeneric hybrid [Elytrigia repens (L.) Nevski × Pseudoroegneria spicata (Pursh) Love], and Russian wildrye [Psathyrostachys juncea (Fisch.) Nevski]. In the first experiment, roots from single-species field plots were washed from soil cores, dried, ground, and mechanically mixed in preselected alfalfa-grass ratios in which the percentage of grass varied from 0 to 100. Equations to measure the proportion of alfalfa or grass were developed from near infrared reflectance data using 84 randomly selected samples. In the second experiment, the 5 plant species were grown in greenhouse pots in pure stands and in binary mixtures that included all combinations of the grasses. Root systems were separated while attached to the topgrowth, dried, and ground. Tissues from single species treatments were mixed and calibration equations developed from these mixtures were used to estimate the proportion of alfalfa and the proportion of grass in samples. Samples contained either one type of root or a mixture of roots in proportions similar to those that occurred naturally in the pots. Coefficients of determination (r2) between the estimated and the actual root mass ratios ranged from 0.92 to 0.99. Determination of the proportion of grass in the samples was more accurate and precise than determination of the proportion of alfalfa. After the appropriate calibration equations have been developed, NIRS is more efficient than hand separation for estimating alfalfa-grass root mass ratios. The utility of the techniques can be increased by developing equations that encompass more complex mixtures and a wider range of environmental circumstances.
    • Determining Common Use Grazing Capacities by Application of the Key Species Concept

      Smith, A. D. (Society for Range Management, 1965-07-01)
      Correct substitution rates of one grazing animal for another under common use take place at uniform rates, being governed at any point by the utilization standard of some single species. The capacity under common use may be greater than that realized with the less suited animal alone, or greater than either animal alone, depending upon the particular combination of animal numbers and the particular range.
    • Determining Correct Stocking Rate on Range Land

      Stoddart, L. A. (Society for Range Management, 1960-09-01)
    • Determining Drought on California’s Mediterranean-Type Rangelands, The Noninsured Crop Disaster Assistance Program

      George, M. R.; Larsen, R. E.; McDougald, N. M.; Vaughn, C. E.; Flavell, D. K.; Dudley, D. M.; Frost, W. E.; Striby, K. D.; Forero, L.C. (Society for Range Management, 2010-06-01)
    • Determining Equitable Grazing Fees for Washington Department of Natural Resources Land

      Harris, G. A.; Hoffman, W. R. (Society for Range Management, 1963-09-01)
    • Determining Forage Weight on Southern Forest Ranges

      Campbell, R. S.; Cassady, J. T. (Society for Range Management, 1949-01-01)
    • Determining Grazing Use by Cow-chip Counts

      Julander, Odell (Society for Range Management, 1955-07-01)
    • Determining Range Condition from Frequency Data in Mountain Meadows of Central Idaho

      Mosley, J. C.; Bunting, S. C.; Hironaka, M. (Society for Range Management, 1986-11-01)
      Although a useful method for monitoring changes in species composition, frequency sampling does not provide herbage production or cover data needed to use existing range condition guides. Responding to this need, frequency sampling procedures were investigated for determining range condition. Eighteen mountain meadow sites were sampled with 100 nested frequency quadrats. These quadrats had 5 plot sizes contained (nested) within 1 frame: 5×5 cm, 10×10 cm, 25×25 cm, 25×50 cm, and 50×50 cm. Rooted frequency of occurrence within each plot size was recorded by species. Discriminant analysis related a site's frequency data to its known range condition class, resulting in 2 range condition guides for mountain meadows based on frequency data. One guide was formulated with data from the 10×10-cm quadrat size, and a second guide was based on summed data from the 4 largest plot sizes. Both guides had equal resolution, correctly classifying 15 of 18, or 83%, of sites examined. Our procedures should prove valuable in developing condition guides based on frequency data in other areas and in other vegetation types.
    • Determining Range Site Potential on Annual Rangeland

      Monette, Nora H.; Menke, John W. (Society for Range Management, 1979-02-01)
    • Determining Rangeland Species Palatability: Application of Principal Component Analysis

      Raufirad, Valiollah; Azadi, Hossein; Ebrahimi, Ataollah; Bagheri, Setareh (Society for Range Management, 2016-12-01)
      On the Ground • Since plant palatability affects many aspects of sustainable rangeland management, including grazing capacity and grazing behavior, introducing indicators for determining rangeland species palatability can help rangeland managers determine rangeland species palatability accurately and precisely. • The Karsanak rangelands in the Chaharmahal-V-Bakhtiari province in Iran are dominated by a mixture of patchily distributed grasses, forbs, and shrubs, with a high biodiversity of plants, which severely affects rangeland species palatability. • The use of forage quality, secondary compounds, and external plant attributes are expected to help rangeland managers with plant palatability classification and in determining grazing capacity to achieve sustainable rangeland management.
    • Determining the Composition of Herbivore Diets in the Trans-Himalayan Rangelands: A Comparison of Field Methods

      Shrestha, Rinjan; Wegge, Per (Society for Range Management, 2006-09-01)
      In late summer, in a semi-arid mountain range in Nepal, we compared 3 field methods for determining the botanical compositionof herbivore diets. Data were collected from the same animals belonging to 1 herd of domestic yak (Bos grunniens) and 2 herds of mixed smallstock, consisting of domestic goats (Capra hircus) and sheep (Ovis aries). Bite count, feeding site examination,and microhistological analysis of feces gave different estimates of forage categories and plant species in both animal groups. Because yaks grazed in other vegetation communities when not observed for bite-counts and feeding signs, the results from the latter methods could not be compared directly with that from fecal analysis. In smallstock, feeding site examination gave higher estimates of graminoids and lower estimates of shrubs than the other 2 methods, probably because all feeding signs on shrubs were not detected. Bite-counts and fecal analysis gave comparable results, except that forbs were underestimated by fecal analysis, presumably due to their more complete digestion. Owing to the difficulty in collecting samples that are representative of the entire grazing period and the problem of recording feeding signs correctly, both feeding site examination and bite-counts are unsuitable methods for studying the food habits of free ranging domestic and wild herbivores. Microhistological analysis of feces appears to be the most appropriate method, but correction factors are needed to adjust for differential digestion. The systematic use of photomicrographs improves the speed and accuracy of the fecal analysis.
    • Detoxication of Timber Milkvetch by 2,4,5-T and Silvex

      Williams, M. C. (Society for Range Management, 1970-11-01)
      Timber milkvetch, Astragalus miser var. oblongifolius, was treated with esters of 2,4,5-T and silvex at 2 lb./acre. The concentration of miserotoxin, the poison contained in the plant, decreased rapidly after treatment. After 4 weeks, treated plants contained only one-third as much miserotoxin as the controls.
    • Developers of Ecological Site Description Find Benefits in Diverse Collaborations

      Johanson, Jamin; Fernandez-Gimenez, Maria (Society for Range Management, 2015-12-01)
      On the Ground • Ecological site descriptions (ESDs) are intended to provide the best available information relevant to a particular type of land and therefore should draw on multiple sources of information and expertise. • We surveyed participants from 16 interagency ESD projects to understand better the process, benefits, challenges, and keys to success for collaborative ESD development. • Collaborative ESD development involves federal and state agencies, universities, nongovernmental organizations, private landowners, and consultants and provides perceived benefits that greatly outweigh the challenges. • The results of this study may improve the transparency and credibility of ESD development by encouraging the inclusion of diverse stakeholders.
    • Developing a Grazing-tolerant Native Grass for Bluebunch Wheatgrass Sites

      Jones, T. A.; Nielson, D. C.; Carlson, J. R. (Society for Range Management, 1991-06-01)
    • Developing a Useful, Personal Range Science Library

      Vallentine, J. F. (Society for Range Management, 1981-03-01)
    • Developing Effective Rancher and Range Technician Working Relationships

      Heerwagen, A. (Society for Range Management, 1954-09-01)
    • Developing Management Strategies for a Changing Ranch Industry

      Dunn, Barry H. (Society for Range Management, 2008-04-01)
    • Developing Opportunities for Marketing Rangeland

      Scaling, Wilson (Society for Range Management, 1988-08-01)
    • Developing Range Management in Latin America

      Blydenstein, J. (Society for Range Management, 1972-01-01)
      The differences in outlook on the conservation of natural resources and multiple use of rangelands between the United States and the countries of Latin America is stressed and it is shown how technical assistance in the field of range management must take these differences into account. Proposals are made for a phased program for development of integrated grazing land management in Latin America, starting with a range resources evaluation which will be the basis for a limited intensive development of suitable areas in order to alleviate the grazing pressure on the natural vegetation. This development phase should be accompanied by range research for management applications during a second action phase. The requirements and difficulties of implementing such a programme are discussed./Se pone énfasis en las diferencias entre los EE.UU. y los países de América Latina en los puntos de vista sobre la conservación de recursos naturales y el uso múltiple de los pastizales naturales. La asistencia técnica en el campo de manejo de pastizales naturales debe tomar en cuenta estas diferencias. Se propone un programa para el desarrollo de un manejo integrado de las tierras de pastoreo en América Latina, empezando con una evaluación de los recursos forrajeros naturales, la cual formará la base para un desarrollo intensivo pero limitado de las mejores áreas para aliviar la presión de pastoreo sobre la vegetación natural. Al mismo tiempo se inician las investigaciones en manejo de pastizales naturales para su posterior aplicación en la segunda fase del programa. Se indican los requerimientos y dificultades para implementar un programa de este tipo.