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Agronomy Journal Abstract - CLIMATOLOGY

Leaf and Stem Area Relationships to Masses and Their Height Distributions in Native Grasses


This article in AJ

  1. Vol. 92 No. 2, p. 225-230
    Received: Apr 5, 1999

    * Corresponding author(s): retta@weru.ksu.edu
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  1. Amare Retta *a,
  2. Dean V. Armbrustb,
  3. Lawrence J. Hagenb and
  4. Edward L. Skidmoreb
  1. a Research Assistant Professor, Dept. of Agronomy, USDA-ARS, Kansas State Univ., Manhattan, KS 66506 USA
    b Research Leader, USDA-ARS, Kansas State Univ., Manhattan, KS 66506 USA


A recently developed wind erosion model (wind erosion prediction system, WEPS) for crop lands is being extended for estimating soil erosion from rangelands, military lands, and desert ecosystems. Wind velocity near the soil surface is calculated as a function of the aerial distribution of stem silhouette area and leaf area of both live plants and standing residue. Grasses either dominate or form a significant part of the plant species growing in the noncrop lands of the world. Several grass species were studied to determine the aerial distribution of stem and leaf masses and areas. Plant samples were taken weekly from pure stands of big bluestem (Andropogon gerardii Vitman), switch grass (Panicum virgatum L.), little bluestem [Schizachyrium scoparium (Michx.) Nash], Indian grass [Sorghastrum nutans (L.) Nash], gamagrass (Tripsacum dactyloides L.), blue grama [Bouteloua gracilis (Kunth) Lag. ex Griffiths), and sideoats grama [Bouteloua curtipendula (Michx.) Torr.]. Plants were cut from a 0.2 m2 area and five tillers were randomly selected and cut into five equal segments. Leaves and stems were separated and their areas and dry weights were measured. For each species a straight line with a zero intercept fit the data of leaf area vs. leaf mass with r 2 ≥ 0.87. Stem area vs. stem mass data fit a power function with r 2 ≥ 0.92. Normalized leaf and stem masses were fit to a hyperbolic tangent (r 2 ≥ 0.96) and exponential (r 2 ≥ 0.98) functions, respectively. The empirical regression coefficients obtained for each species will be included in the WEPS plant growth data base.

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