• A Comparison of Four Distance Sampling Techniques in South Texas Live Oak Mottes

      Beasom, S. L.; Haucke, H. H. (Society for Range Management, 1975-03-01)
      Four distance sampling techniques; point-center-quarter (PCQ), random pairs (RP), nearest neighbor (NN), and closest individual (CI) were compared to total counts to determine accuracy of density and relative frequency approximations in a live oak (Quercus virginiana) motte vegetative type in South Texas. The PCQ method was the most accurate for estimating density, followed in decreasing order by RP, CI, and NN. Only the NN approximation was significantly different from the actual density. The PCQ method also provided the most accurate relative frequency approximations, followed in decreasing order by RP, NN, and CI.
    • A Comparison of Four Methods Used to Determine the Diets of Large Herbivores

      McInnis, M. L.; Vavra, M.; Krueger, W. C. (Society for Range Management, 1983-05-01)
      Esophageal fistulation, stomach content analysis, fecal analysis, and forage utilization were compared as techniques for determining food habits of large herbivores. Each technique was evaluated based upon information collected using bi-fistulated (esophageal and rumen) sheep during 2 study phases. In the first study phase, microscope slide mounts were made of plant fragments collected from the esophagus, rumen, and feces of 10 confined sheep fed a hand-composited mixture of forage. Dietary composition as determined by each technique was compared to the original feed. Stomach content analysis and fecal analysis produced dietary estimates higher in grasses and lower in forbs than the known feed values. Esophageal fistulation results were not significantly different from the known feed values. In the second study phase, esophageal, rumen, and fecal collections were gathered from 16 sheep grazing a common plant community. Ocular estimates of forage utilization were made concurrently. All data were converted to percent composition on a dry weight basis for comparisons. Significant differences in percent diet composition among techniques occurred for 18 of the 31 plant species consumed. Diets determined by stomach content analysis and fecal analysis were significantly higher in grasses and lower in forbs than those determined by esophageal fistulation and ocular estimates of utilization.
    • A comparison of frontal, continuous, and rotation grazing systems

      Volesky, J. D.; O'Farrell, F. De Achaval; Ellis, W. C.; Kothmann, M. M.; Horn, F. P.; Phillips, W. A.; Coleman, S. W. (Society for Range Management, 1994-05-01)
      Two 2-year trials were conducted to evaluate and compare frontal, continuous, and 2-paddock rotation grazing systems on 'Plains' Old World bluestem (Bothriochloa ischaemum (L.) Keng.). Frontal grazing allows livestock a continuous opportunity to graze fresh forage via a livestock-pushed, sliding fence which allocates and controls grazing within a pasture. Trial 1 treatments included frontal grazing at a very high stocking density of 13.3 head ha-1 and continuous grazing at 4 stocking densities described as low, moderate, high, and very high. The mechanical design and components of our frontal grazing system were quite adequate in terms of the system's operation and interaction with the livestock herd. Significant (P < 0.05) linear relationships were found for regressions of daily gain on stocking rate and grazing pressure index, and for gain ha-1 on stocking rate and grazing pressure index. Year effects were evident in all regressions. Trial 2 treatments included frontal, continuous, and rotation grazing systems initially stocked at 6.7 head ha-1. Mid-season reductions in stocking density were made in continuous and rotation grazing to ensure that these treatments would have adequate forage to continue until frontal grazing completed its second cycle and to achieve an end-of-season standing crop which was similar in all 3 treatments. Season-long daily gains under frontal grazing were not significantly different compared to continuous grazing (P > 0.05); however, they were less than those under rotation grazing (P < 0.05). Frontal grazing provided about 100 more steer-days per hectare of grazing than either continuous or rotation grazing. However, steer production was not significantly different among treatments and averaged 296 kg ha-1 (P > 0.05).
    • A Comparison of Grass Growth on Different Horizons of Three Grassland Soils

      Joy, C. R.; Helwig, L.; Reiger, T.; Supola, M. (Society for Range Management, 1954-09-01)
    • A Comparison of In Vitro and In Vivo Feed Digestibility by White-tailed Deer

      Ruggiero, L. F.; Whelan, J. B. (Society for Range Management, 1976-01-01)
      Two captive, rumen-fistulated, white-tailed deer (Odocoileus virginianus) were used to evaluate the two-stage in vitro microdigestion technique as an estimator of in vivo dry-matter digestibility. The technique provided digestibility percentages that departed only slightly from in vivo values for the artificial ration tested.
    • A Comparison of Line Intercepts and Random Point Frames for Sampling Desert Shrub Vegetation

      Brun, J. M.; Box, T. W. (Society for Range Management, 1963-01-01)
    • A Comparison of Methods of Estimating Plant Cover in an Arid Grassland Community

      Winkworth, R. E.; Perry, R. A.; Rossetti, C. O. (Society for Range Management, 1962-07-01)
    • A Comparison of Methods of Renovating Old Stands of Crested Wheatgrass

      Lorenz, R. J.; Rogler, G. A. (Society for Range Management, 1962-07-01)
    • A comparison of methods to determine plant successional stages

      Winslow, S. R.; Sowell, B. F. (Society for Range Management, 2000-03-01)
      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.
    • A Comparison of Rhizobium Strains for Effective Nodulation in Kenya Clover (Trifolium semipilosum)

      Moore, Duane G.; Britten, E. J. (Society for Range Management, 1964-11-01)
    • A Comparison of Sampling Methods in Dense Herbaceaous Pasture

      Poissonet, P. S.; Poissonet, J. A.; Gordon, M. P.; Long, G. A. (Society for Range Management, 1973-01-01)
      Several methods of vegetation sampling were compared in a very homogeneous herbaceous vegetation: Needle points, double metre points, bayonet points, line transects, area measurements, and harvesting with sorting and weighing. Consistent curvilinear relationships were found between species frequencies, interceptions, and biomasses obtained by several methods. These constant relationships allow the estimation of yields from the double metre points by simple and fast observations. The shape of the curves suggests some ecological relationship between the vegetation attributes analyzed.
    • A comparison of satellite-derived vegetation indices for approximating gross primary productivity of grasslands

      Zhou, Y.; Zhang, L.; Xiao, J.; Chen, S.; Kato, T.; Zhou, G. (Society for Range Management, 2014-01)
      Gross primary productivity (GPP) is a key component of ecosystem carbon fluxes and the carbon balance between the biosphere and the atmosphere. Accurate estimation of GPP is essential for quantifying plant production and carbon balance for grasslands. Satellite-derived vegetation indices (VIs) are often used to approximate GPP. The widely used VIs include atmospherically resistant vegetation index, enhanced vegetation index (EVI), normalized difference greenness index, normalized difference vegetation index, reduced simple ratio, ratio vegetation index, and soil-adjusted vegetation index (SAVI). The evaluation of the performance of these VIs for approximating GPP, however, has been limited to one or two VIs and/or using GPP observations from one or two sites. In this study, we examined the relationships between the nine VIs derived from the moderate resolution imaging spectroradiometer (MODIS) and tower-based GPP at five eddy covariance flux sites over the grasslands of northern China. Our results showed that the nine VIs were generally good predictors of GPP for grasslands of northern China. Overall, EVI was the best predictor. The correlation between EVI and GPP also declined from the south to the north, indicating that EVI and GPP exhibited closer relationships in more southerly sites with higher vegetation cover. We also examined the seasonal influence on the correlation between VIs and GPP. SAVI exhibited the best correlation with GPP in spring when the grassland canopy was sparse, while EVI exhibited the best correlation with GPP in summer when the grassland cover was dense. Our results also showed that VIs could capture variations in observed GPP better in drought period than in nondrought period for an alpine meadow site because of the suppression of vegetation growth by drought. © 2014 The Society for Range Management.
    • A Comparison of Seeded Grasses Under Grazing and Protection on a Mountain Brush Burn

      Frischknecht, N. C.; Plummer, A. P. (Society for Range Management, 1955-07-01)
    • A comparison of soil chemical characteristics in modified rangeland communities

      Dormaar, J. F.; Willms, W. D. (Society for Range Management, 2000-07-01)
      The effects of converting native prairie to simplified agronomic communities on primary production and soil quality are expected to differ over the short-term. A study was initiated at 4 locations: a Mixed Prairie with Stipa comata Trin. Rupr. dominant in the Brown Soil Zone (1994), a Mixed Prairie with S. comata and S. viridula Trin. dominant in the Dark Brown Soil Zone (1993), and 2 in the Fescue Prairie with Festuca campestris Rydb. dominant in the Black Soil Zone (1993). At each of the 4 sites, 5 treatments representing common production systems were seeded as monocultures [2 grass species, alfalfa (Medicago sativa L. 'Beaver'), and 2 spring wheat (Triticum aestivum L. 'Katepwa) seeded as either continuous or as wheat-fallow], and 1 treatment consisting of abandoned cultivation were compared with a native community in a randomized complete block design with 4 replicates. One site in the Black Soil Zone was an overgrazed prairie (2.4 animal unit month ha-1 since 1949) and a second was mostly ungrazed for the previous 50 years with occasional light fall-grazing. Soils of the modified communities were different (P < 0.05) than of the native community with respect to percent carbon and nitrogen, concentration of monosaccharides, and concentration of most phosphorus constituents. Modifying the community through cultivation and seeding usually caused a reduction in the measured variable except for NaHCO3 inorganic phosphorus that increased. Cultivation rather than the plants of the new community was believed responsible for most of the observed changes in C, N, and various P fractions and the loss of water-stable aggregates remaining on the 2.0 and 1.0 mm sieves. Although the contribution of seeded species on the chemical and physical characteristics would not have been significantly expressed in 2 to 3 years and many more years would be required to reach a steady state, monosaccharide distribution had nevertheless started to shift to one that was plant-affected.
    • A Comparison of the Charting, Line Intercept, and Line Point Methods of Sampling Shrub Types of Vegetation

      Heady, H. F.; Gibbens, R. P.; Powell, R. W. (Society for Range Management, 1959-07-01)
    • A Comparison of the Line Interception and Quadrat Estimation Methods of Determining Shrub Canopy Coverage

      Hanley, T. A. (Society for Range Management, 1978-01-01)
      The line-interception and Daubenmire's 0.1 m2 quadrat estimation methods of determining canopy coverage were compared for four densities of big sagebrush in northwestern Nevada. Results indicated that the methods provide comparable estimates. The line-interception method is preferable to 0.1 m2 quadrats where high levels of precision and confidence are required, but the 0.1 m2 quadrat method may be preferable where lower levels of precision and confidence are acceptable. Fewer man-minutes of time are required by either method for one person working alone than for two people working together.
    • A Comparison of the Line-Interception, Variable Plot and Loop Methods as Used to Measure Shrub-Crown Cover

      Kisinger, F. E.; Eckert, R. E.; Currie, P. O. (Society for Range Management, 1960-01-01)
    • A Comparison of the Loop and Point Methods of Analyzing Vegetation

      Cook, C. W.; Box, T. W. (Society for Range Management, 1961-01-01)
    • A Comparison of Three Methods for Estimating Forage Disappearance

      Sharrow, S. H.; Motazedian, I. (Society for Range Management, 1983-07-01)
      Three methods of calculating forage disappearance from forage standing crop present on mowed versus protected plots were compared to the actual amount of forage harvested from mowed plots. The method most widely used by range scientists, the difference method, displayed a marked tendency to overestimate forage disappearance during periods of rapid plant growth or when plots were protected for more than 3 weeks. More accurate estimates of forage disappearance were generally obtained using formulae suggested by Linehan et al. (1947) and Bosch (1956) than could be obtained by the difference method.