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United States Department of Agriculture

Agricultural Research Service

Title: Microbial Aspects of Soil Quality and Nutrient Cycling

Author
item Kennedy, Ann

Submitted to: Steep Annual Report
Publication Type: Research Notes
Publication Acceptance Date: December 1, 1996
Publication Date: N/A

Interpretive Summary: Soil is a key natural resource interacting with aboveground plant and animal communities. Critical to the maintenance of any ecosystem, soil, when managed effectively, contributes to the success of sustainable agriculture. Soil quality is considered to be key to agricultural sustainability. Assessing the differences in soil quality among various management systems will aid in the development of practices that maintain soil quality and enhance crop productivity. Air quality problems resulting from displaced soil or dust particulates are mainly unresolved because current technology often does not enable identification of the nonpoint sources of pollution. To implement control measures to reduce nonpoint dust emissions, it is necessary to distinguish among the relative contributions from specific regions upwind of the receptor area. Soils are composed of distinct microbial communities, thus biological analyses may aid in identifying the sources of fugitive dust.

Technical Abstract: Soil quality is a key component in the development of Best Management Practices. To identify soil building management practices, this research focused on assessing soil quality through the use of microbial analyses. Recognizing the lack of information on soil microbial communities and diversity of those systems, we investigated the differences in microbial activity and communities among management systems. In our studies of biosolids application to agricultural soils, changes were either positive (greater straw production) or negative (pH, EC, P, Zn, and microbial activity). In the burn-low till studies, the type of disturbance influenced the overall activity and microbial community distribution. In CRP takeout studies, differences were seen in the type of CRP take-out. Fatty acid profile analyses were used to differentiate dissimilar soils. We assembled a 'library' of fatty acid fingerprints for soils of the Columbia Plateau area, which separated into five clusters of biological groups. The successful development of this method will provide a powerful tool for identifying sources of air-borne particulate matter. Samples of dust from air around Spokane, WA were most similar to fingerprints of soil from urban areas. Only on extremely windy and dusty days did patterns from air samples have somewhat similar patterns to agricultural soils. This new technology will help target nonpoint, as well as point sources of dust, etc., and provide a powerful tool for developing policies to control dust pollution that are fair to farmers, developers and other land users. In residue decomposition studies, we found that cultivars of wheat and barley differed in their decomposition rates and these may be used in decisions to alter residue amounts.

Last Modified: 4/16/2014
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