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United States Department of Agriculture

Agricultural Research Service

Research Project: DEVELOP AND IMPROVE STRATEGIES FOR MANAGEMENT OF IRRIGATED AGRICULTURAL CROPS AND SOILS

Location: Northwest Irrigation and Soils Research

Title: Development of vegetation based soil quality indices for mineralized terrane in arid and semi-arid ecosystems

Authors
item Blecker, Sw -
item Stillings, Ll -
item Mcamacher, Mc -
item Ippolito, James
item Decrappeo, NM -

Submitted to: Ecological Indicators
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 9, 2012
Publication Date: March 9, 2012
Citation: Blecker, S., Stillings, L., Mcamacher, M., Ippolito, J.A., Decrappeo, N. 2012. Development of vegetation based soil quality indices for mineralized terrane in arid and semi-arid ecosystems. Journal of Ecological Indicators. 20:65-74.

Interpretive Summary: We developed a soil quality index in arid and semi-arid ecosystems of the Western US impacted by different types of geologic mineralization using the relationship between vegetation community parameters and soil abiotic and biotic properties. We found that the parameters and combinations to arrive at a soil quality index for a given site cannot be correlated or compared with that of another site. This soil quality index approach provided a means of quantifying disturbed ecosystem recovery resulting from mining, and could be applied to other disturbances in a way that readily distills the information for potential use by land managers. However, severely disturbed areas with little to no aboveground biomass have likely crossed an ecological threshold that precludes the use of this type of monitoring tool.

Technical Abstract: Soil quality indices are often management driven and attempt to describe key relationships between above- and below-ground parameters. In terrestrial systems, indices that were initially developed and modified for agroecosystems have been applied to non-agricultural systems in increasing number. We developed a soil quality index in arid and semi-arid ecosystems of the Western US impacted by different types of geologic mineralization using the relationship between vegetation community parameters and soil abiotic and biotic properties. We analyzed these relations in soils associated with three different mineralization types: podiform chromite, Copper/Molybdenum porphyry, and acid-sulfate gold vein systems at four different sites in California and Nevada. Soil samples were collected from undisturbed soils in both mineralized and nearby unmineralized substrates as well as from waste rock and tailings. Aboveground net primary productivity, canopy cover and shrub density were measured for the vegetative communities. Minimum data sets were developed based on correlations between the soil and vegetation parameters, refined using principal components analysis, scored using non-linear functions, and combined into an overall soil quality index. The indices are comprised of one or two microbial parameters and three to six abiotic parameters, the latter consisting of nutrients and metals. Given the preliminary development of this approach, the parameters and combinations to arrive at a soil quality index for a given site cannot at this time be correlated or compared with that of another site. This soil quality index approach provides a means of quantifying disturbed ecosystem recovery resulting from mining, and could be applied to other disturbances in a way that readily distills the information for potential use by land managers.

Last Modified: 4/17/2014
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