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Visual Obstruction: Weight Technique for Estimating Production on Northwestern Bunchgrass Prairie Rangelands

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dc.creator Damiran, Daalkhaijav
dc.creator DelCurto, Timothy
dc.creator Darambazar, Enkhjargal
dc.creator Clark, Abe A.
dc.creator Kennedy, Patricia L.
dc.creator Taylor, Robert
dc.date.accessioned 2007-07-09T20:50:37Z
dc.date.available 2007-07-09T20:50:37Z
dc.date.issued 2007-06
dc.identifier.citation Damiran, D., T. DelCurto, E. Darambazar, A. A. Clark, P. L. Kennedy, and R. V. Taylor. 2007. Visual obstruction: weight technique for estimating production on northwestern bunchgrass prairie rangelands. In: Proceedings of Western Section, American Society of Animal Sciences 58:225-228. en
dc.identifier.uri http://hdl.handle.net/1957/5826
dc.description none en
dc.description.abstract The estimation of standing crop is important in the management of rangeland resources. Direct measurements by clipping, drying, and weighing of herbaceous vegetation are time-consuming and labor-intensive. Therefore, non-destructive methods for efficiently and accurately estimating standing crop are needed in rangeland forage management. We assessed a visual obstruction (VO) technique to estimate standing crop (SC) of northwest native bunchgrass communities at The Nature Conservancy’s Zumwalt Prairie Preserve in northeastern Oregon. This method involves obtaining a height-density index by measuring the height of a pole that is obscured by vegetation when viewed from the side. Five hundred seventy six plots (0.5 m2) were subjected to VO measurement; and subsequently, all vegetation within a plot was clipped to ground level. Only current year’s crop was taken. Regression analysis was used to evaluate the relationships of VO to standing crop, with standing crop as the dependent variable. Total standing crop was 1261 ± 51 kg∙ha-1 and mean of VO measurement was 12.8 ± 0.4 cm for vegetation in the study site. By growth habit of plants, standing crops were 688 ± 26, 13 ± 26, 416 ± 26, and 144 ± 26 kg∙ha-1 for grasses, grasslikes, forbs, and shrubs, respectively, and all growth habits differed from each other (P < 0.01). A positive (P < 0.01) linear relationship occurred between VO and SC measurements, however, correlation was low with only 46% of the variation in standing crop being attributable to VO (y, kg∙ha-1 = 270.58 + 77.66x, cm; r2 = 0.46, n = 576). In heterogeneous mid-height bunchgrass communities like the Zumwalt Prairie Preserve, the VO technique will not accurately predict standing crop although many wildlife investigators will still find it useful for describing vegetative structure in these communities. Consequently, we recommend that, if considering VO as a surrogate for SC, investigators should calibrate VO technique against clip plots to evaluate applicability to their situation. en
dc.description.sponsorship The project was supported by the National Research Initiative of the USDA Cooperative State Research, Education and Extension Service, grant number 2006-35101-16572, The Nature Conservancy and Oregon State University’s Eastern Oregon Agricultural Research Center. en
dc.format.extent 136103 bytes
dc.format.mimetype application/pdf
dc.language.iso en_US en
dc.publisher American Society of Animal Sciences en
dc.subject Biomass en
dc.subject Non-destructive Technique en
dc.subject Rangelands en
dc.subject Robel Pole en
dc.subject Visual Obstruction en
dc.title Visual Obstruction: Weight Technique for Estimating Production on Northwestern Bunchgrass Prairie Rangelands en
dc.type Research Paper en
dc.description.digitization pdf en


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