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United States Department of Agriculture

Agricultural Research Service

Title: Potential Biological Indicators of Soil Quality

Authors
item Smith, Jeffrey
item Halvorson, J - WASHINGTON STATE UNIV

Submitted to: Journal of Soil Biology and Biochemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 1, 1995
Publication Date: N/A

Interpretive Summary: The concept of soil quality is receiving increasing interest worldwide due to the realization that farming practices are degrading the soil resource. We are faced with the problem of developing sustainable farming practices that will increase soil quality. To accomplish this we must be able to evaluate the practices rather quickly and thus need indicators of soil quality that change quickly in response to management practices. Biological indicators have been suggested as a quickly changing attribute of soils. We evaluated an agricultural field for soil quality based on several biological indicators to get a feel of how we would interpret such biological data in relationship to soil quality. We present data that shows the problems in assessing soil quality due to spatial variability in biological variables. This study gives us insight on how we must go about measuring indicators of soil quality in order to obtain meaningful results.

Technical Abstract: Soil quality is the key factor for sustainable agricultural systems and for evaluation of natural ecosystems. To evaluate soil quality a number of soil attributes will need to be measured, evaluated and integrated into a soil quality index. Soil biological parameters are thought to be sensitive indicators of changes in soil quality but are also highly variable spatially. This study was conducted to determine the spatial variability and correlation of biological parameters on a field scale with respect to soil quality. The variability of the biological parameters decreased in the order of respiration> enzyme assays and qCO2 > microbial biomass C. The distribution frequency of all parameters except respiration were normal although the spatial distribution across the landscape was highly variable. The biological parameters showed poor correlation with each other when all data points were considered however when grouped in smaller sections the correlation's were more consistent with observed patterns across the field. To accurately asses soil quality using in part biological indicators consideration of spatial and temporal variability, soil conditions and other controlling factors must be taken into account.

Last Modified: 10/26/2014
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