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United States Department of Agriculture

Agricultural Research Service

Title: The Potential of Diffuse Reflectance Spectroscopy for the Determination of Carbon Inventories, Sequestration, and Fate in Soils

Authors
item Reeves Iii, James
item MCCARTY, GREGORY
item Mimmo, Tanja - UNIVERSITY OF BOLOGNA, IT

Submitted to: Environmental Pollution
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 3, 2001
Publication Date: February 5, 2002

Interpretive Summary: Spectroscopy uses the interaction of light with materials to determine composition. Near- and mid-infrared radiation are two forms of spectroscopy which use light beyond the range of human sight. Investigations have shown that near- and mid-infrared reflectance spectroscopy can accurately determine organic carbon (biological in source) in soil. Efforts have also demonstrated that both can differentiate between organic- and inorganic-carbon in soils, but that the mid-infrared produces more accurate calibrations. These efforts demonstrate that these methods hold great promise for laboratory soil analysis. However, the greatest benefit would come with in situ (in place) determinations where factors such as particle size, sample heterogeneity and moisture could be important factors. While increasing particle size in samples can adversely effect on calibration accuracy, efforts have demonstrated that the scanning of larger samples can overcome this problem, but the effects of moisture have not been fully explored. While under in situ conditions carbon distribution and sample heterogeneity are a problem for any analytical method, the rapid analysis possible with spectroscopic techniques will allow many more samples to be analyzed, thus reducing the errors these factors induced. In conclusion, near- and mid-infrared spectroscopy have great potential for providing the carbon values needed for carbon sequestration studies.

Technical Abstract: Investigations have shown that near- and mid-infrared reflectance spectroscopy can accurately determine organic-C in soil. Efforts have also demonstrated that both can differentiate between organic- and inorganic-C in soils, but that the mid-infrared produces more accurate calibrations. These efforts demonstrate that these methods hold great promise for laboratory soil analysis. However, the greatest benefit would come with in situ determinations where factors such as particle size, sample heterogeneity and moisture could be important factors. While increasing particle size in samples can adversely effect on calibration accuracy, efforts have demonstrated that the scanning of larger samples can overcome this problem, but the effects of moisture have not been fully explored. While under in situ conditions C distribution and sample heterogeneity are a problem for any analytical method, the rapid analysis possible with spectroscopic techniques will allow many more samples to be analyzed, thus reducing the errors these factors induced. In conclusion, near- and mid-infrared spectroscopy have great potential for providing the C values needed for C sequestration studies.

Last Modified: 9/29/2014
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