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United States Department of Agriculture

Agricultural Research Service

Title: Spatial Variability of Biological Indicators of Soil Quality

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

Submitted to: Science of Soils
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 15, 2000
Publication Date: N/A

Interpretive Summary: In the last 10 years there has been an increased interest in the concept of soil quality because it relates to the health of the global biosphere. In a global context soil quality affects not only soil productivity but is also a significant factor governing environmental quality, human and animal health and food safety and quality. Soil quality is of similar importance to humankind as air and water quality, thus it is apparent that simply protecting soil quality by slowing soil degradation or maintaining the current level of soil health will not provide the soil quality that will be needed for future generations. Soil quality must be improved as well. Soil quality per se is not a new concept, having for centuries been related to soil degradation. The degradation of soil or soil quality from human activities has affected many civilizations over the last 7,000 years. Recent recognition of the importance of soil quality is evidenced by the worldwide activity to identify and quantify land degradation. Programs of the United Nations Environment Programme, the Food and Agriculture Organization and the International Soil Reference and Information Center have attempted to map human-induced soil degradation worldwide. Other soil assessment programs both scientific and political have been developed in Africa, Australia, Canada, Europe and the United States. However, in addition soil quality is now being viewed in the broader role of being the central linkage necessary for sustainable agriculture and ecosystem health.

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 in space eand time. 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 little 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: 10/20/2014
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