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Michael A. Smith

Bio: Michael A. Smith is an academic researcher from University of Wyoming. The author has contributed to research in topics: Grazing & Stocking. The author has an hindex of 19, co-authored 44 publications receiving 1198 citations.

Papers
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Journal ArticleDOI
TL;DR: In this article, the authors compared continuous, Qpasture rotationally de&r&, and short-duration rotation grazing on mixed-grass range near Cheyenne, Wyo. from 1982 through 1987.
Abstract: Manipulating stocking rate and duration of grazing is fundamental to range management. It has been claimed that rotation grazing systems wiil increase stocking capadty of range whiie maintaining or improving anhnal gains, range condition, and forage production. To test these claims, we compared continuous, Qpasture rotationally de&r&, and &paddock short-duration rotation grazing on mixed-grass range near Cheyenne, Wyo. from 1982 through 1987. Grazing pmsures ranged from 19 to 81 steerdays per tonne of forage dry matter produced. Steers were weighed biweekly; forage production, utilization, and botanical composition were estimated by clipping; and basai cover was estimated by inclined point frame. Basal cover of litter and bare ground responded to stocking rate or grazing systems, but basal cover of vegetation was affected only by years. Steer average daily gain decreased as grazing pressure increased (r’ = 0.66); systems had no significant effect. The most profitable stocking rate at 1986-87 costs and prices was approximately 60 to 80% above SCS recommendations, but the increase in return was small and range conditions and forage production probably could not be maintained a1 this rate.

216 citations

Journal ArticleDOI
TL;DR: In this article, the authors compared season-long, 4-pasture rotationally deferred, and 8-paddock time-controlled rotation grazing on mixed-grass rangeland near Cheyenne, Wyo. from 1982 through 1994.
Abstract: Rotation grazing strategies have been proposed to increase stocking capacity, improve animal gains, and improve forage production and range condition. We compared continuous or season-long, 4-pasture rotationally deferred, and 8-paddock time-controlled rotation grazing on mixed-grass rangeland near Cheyenne, Wyo. from 1982 through 1994. Stocking rates under light, moderate and heavy grazing averaged 21.6, 47.0, and 62.7 steer-day ha-1; grazing pressures were 11.0 to 90.1 steer-day Mg-1 of forage dry matter produced. We estimated above and below-ground biomass, botanical composition and basal cover. Bare ground and cover of warm-season grasses, forbs, and lichens were greater under heavy stocking; cover of litter, western wheatgrass, and total cool-season graminoids were greater under light stocking. Stocking rate and grazing strategy had no effect on above-ground biomass and little effect on below-ground biomass. Under heavy stocking, percent of above-ground biomass contributed by forbs increased, especially under time-controlled rotation grazing, and that of western wheatgrass decreased. Otherwise, effects of grazing strategy, level vs. slope, and north vs. south slope on vegetation were insignificant. Steer average daily gain decreased linearly as grazing pressure increased (r2 = 0.44); grazing strategies had no significant effect. When cattle prices are favorable, the stocking rates that are most profitable in the short run may be high enough to reduce range condition.

119 citations

Journal ArticleDOI
TL;DR: A 3-year experiment designed to quantify the spatial and temporal utilization patterns of range sites by beef cattle on summer foothill range was conducted on the Wick Brothers Management Unit of the Wyoming Game and Fish Commission, where coarse upland, very shallow and shallow loamy sites were not preferred; however, site preference varied as areas further from water were utilized.
Abstract: A 3-year experiment designed to quantify the spatial and temporal utilization patterns of range sites by beef cattle on summer foothill range was conducted on the Wick Brothers Management Unit of the Wyoming Game and Fish Commission, 8 km w. of Arlington, Wyo. The grazing seasons, in replicate pastures, were from 15 July-9 August, 15 June-26 July, and 15 June-2 August in 1980, 1981, and 1982, respectively. Daily observations were made of radio-telemetry collared cattle (3 per pasture). Cattle dispersion was constrained by the spatial distribution of water and slope. Across 3 seasons, 77% of observed use was within 366 m of water. Approximately 65% of the land area was beyond 723 m from water and sustained only 12% of observed use. Cattle concentrated use (79%) on slopes less than 7%. Consequently 35% of the area, on or surrounded by slopes > 10%, received only 7% of observed use. Loamy, grazable woodland and wetland/subirrigated range sites were most preferred and accounted for over 65% of observed use while occupying less than 35% of the land area. Overall, coarse upland, very shallow and shallow loamy sites were not preferred; however, site preference varied as areas further from water were utilized. Observed use was significantly (P < 0.10) correlated (r 0.41 to 0.69) with standing crop and crude protein standing crop over various growth form characteristics of the forage component. Associated stepwise regression models accounted for 44 to 73% of the variation in observed use over the 1982 grazing season. As the forage complex became more similar, in terms of standing crop and crude protein content, significantly less (P < 0.05) variation in use was accounted for by the forage variables (0-37%).

116 citations

Journal ArticleDOI
TL;DR: The effects of stocking rate and grazing system on gains of yearling beef cattle grazing rangelands have largely been addressed in short-term studies.

71 citations

Journal ArticleDOI
TL;DR: This technique to estimate canopy volume of shrubs that used a formula [2/3piH (A/2 x B/2)] derived from the basic ellipsoid volume formula is evaluated and is precise, efficient, and repeatable.
Abstract: Cover methods quantify vegetative communities in only 2 dimensions. The addition of height measurements to cover data, resulting in canopy volume estimates, provide a more practical level of description for shrub communities. We evaluated a technique to estimate canopy volume of shrubs that used a formula [2/3piH (A/2 x B/2)] derived from the basic ellipsoid volume formula. Objectives of this study were to determine if there were significant differences among means of repeated observations on sample units: (1) among observers; (2) within observers; and (3) between sample periods when using this technique. At 2 locations in Wyoming, 10 planeleaf willow (Salix planifolia var. planifolia Pursh) plants along each of 5 randomly established transects were sampled during 2 consecutive periods by 4 observers. Differences among observers were significant at both sites (P 0.05) at either site. Mean canopy volume did not vary significantly (P > 0.05) between sample periods when averaged across observers. Estimated sample sizes ranged between 2 and 31 transects depending on the desired sampling precision and confidence level. The average time per transect among all observers decreased from 13 minutes (SD = 3.7) in sample period 1 to 9 minutes (SD = 1.3) in sample period 2. Using this method, managers can better describe and monitor trends in the structural diversity of shrub communities. This canopy volume technique can be applied with minimal training and is precise, efficient, and repeatable. DOI:10.2458/azu_jrm_v55i3_thorne

70 citations


Cited by
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Journal Article
TL;DR: This book by a teacher of statistics (as well as a consultant for "experimenters") is a comprehensive study of the philosophical background for the statistical design of experiment.
Abstract: THE DESIGN AND ANALYSIS OF EXPERIMENTS. By Oscar Kempthorne. New York, John Wiley and Sons, Inc., 1952. 631 pp. $8.50. This book by a teacher of statistics (as well as a consultant for \"experimenters\") is a comprehensive study of the philosophical background for the statistical design of experiment. It is necessary to have some facility with algebraic notation and manipulation to be able to use the volume intelligently. The problems are presented from the theoretical point of view, without such practical examples as would be helpful for those not acquainted with mathematics. The mathematical justification for the techniques is given. As a somewhat advanced treatment of the design and analysis of experiments, this volume will be interesting and helpful for many who approach statistics theoretically as well as practically. With emphasis on the \"why,\" and with description given broadly, the author relates the subject matter to the general theory of statistics and to the general problem of experimental inference. MARGARET J. ROBERTSON

13,333 citations

Journal ArticleDOI
24 Feb 1995-Science
TL;DR: With the addition of a quarter of a million people each day, the world population's food demand is increasing at a time when per capita food productivity is beginning to decline.
Abstract: Soil erosion is a major environmental threat to the sustainability and productive capacity of agriculture. During the last 40 years, nearly one-third of the world's arable land has been lost by erosion and continues to be lost at a rate of more than 10 million hectares per year. With the addition of a quarter of a million people each day, the world population's food demand is increasing at a time when per capita food productivity is beginning to decline.

2,589 citations

Journal ArticleDOI
TL;DR: In this article, applied linear regression models are used for linear regression in the context of quality control in quality control systems, and the results show that linear regression is effective in many applications.
Abstract: (1991). Applied Linear Regression Models. Journal of Quality Technology: Vol. 23, No. 1, pp. 76-77.

1,811 citations

Journal ArticleDOI
TL;DR: A conceptual model was developed to demonstrate how cognitive foraging mechanisms could work within constraints imposed by abiotic factors, and preliminary predictions of the model correspond to observed grazing patterns.
Abstract: Grazing distribution patterns of large herbivores are affected by abiotic factors such as slope and distance to water and by biotic factors such as forage quantity and quality. Abiotic factors are the primary determinants of large-scale distribution patterns and act as constraints within which mechanisms involving biotic factors operate. Usually there is a proportional relationship between the time large herbivores spend in a plant community and the available quantity and quality of forage. This grazing pattern may result from decisions made by animals at different spatial and temporal scales. Foraging velocity decreases and intake rate increases in areas of abundant palatable forage. These non-cognitive mechanisms that occur at smaller spatial scales (bites, feeding stations, small patches) could result in observed grazing patterns. However, large herbivores also appear to select areas (patches and feeding sites) to graze. Optimal foraging models and other models assume animals use "rules of thumb" to decide where to forage. A cognitive mechanism assumes animals use spatial memory in their foraging decisions. With such abilities, large herbivores could return to nutrient-rich sites more frequently than to nutrient-poor sites. Empirical studies indicate that large herbivores have accurate spatial memories and have the ability to use spatial memory to improve foraging efficiency. Body size and perceptual abilities can constrain the choices animals can make during foraging. A conceptual model was developed to demonstrate how cognitive foraging mechanisms could work within constraints imposed by abiotic factors. Preliminary predictions of the model correspond to observed grazing patterns. Recognizing that large herbivores may use previous experiences to decide where to forage may be useful in developing new techniques to modify grazing patterns. Grazing distribution patterns appear to result from decisions and processes made at a variety of spatial and temporal scales.

946 citations

Book
01 Aug 1998
TL;DR: The role of agriculture in U.S. Greenhouse gas emissions is discussed in this paper, where the authors propose a win-win strategy to increase agricultural profits from environmental improvements.
Abstract: Objectives Basic Processes The Greenhouse Process Global Trends in Greenhouse Gas Emissions The Role of Agriculture in U.S. Emissions of Three GHGs The SOC Pool in U.S. Soils and SOC Loss from Cultivation Processes in Governing Emissions from the Pedosphere Plant Action Soil Processes Soil Quality Strategies for Mitigating Emissions from Cropland U.S. Cropland Sustainable Management Studies Soil Erosion Management Land Conversion and Restoration Conversion of Marginal Land Restoration of Degraded Soils Biofuels for Offsetting Fossil Fuel Intensification of Prime Agricultural Land Conservation Tillage and Residue Management Irrigation Water Management Improved Cropping Systems The Carbon Sequestration Potential of Arable Land U.S. Cropland's Overall Potential to Mitigate the Greenhouse Effect Techniques for Sequestration Rates of SOC Sequestration Possible Implementation Obstacles Required Action Conclusions - The Win-Win Strategy Agricultural Profits from Environmental Improvements SOC's Monetary Value SOC's Environmental Value Global Potential Appendix 1: Definitions Appendix 2: Researchable Topics

866 citations