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United States Department of Agriculture

Agricultural Research Service

Research Project: NUTRIENT CYCLING AND UTILIZATION ON ORGANIC DAIRY FARMS

Location: New England Plant, Soil and Water Research Laboratory

Title: Influence of Tillage, Cropping Management, and Nitrogen Source on Humic, Fulvic, and Water-Extractable Organic Matter Fractions: A Fluorescence Study

Authors
item Ohno, Tsutomu - UNIVERSITY OF MAINE
item He, Zhongqi
item Tazisong, Irenus - ALABAMA A&M UNIVERSITY
item Senwo, Zachary - ALABAMA A&M UNIVERSITY

Submitted to: Soil Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 25, 2009
Publication Date: December 15, 2009
Citation: Ohno, T., He, Z., Tazisong, I.A., Senwo, Z.N. Influence of Tillage, Cropping Management, and Nitrogen Source on Humic, Fulvic, and Water-Extractable Organic Matter Fractions: A Fluorescence Study. Soil Science. 174:652-660.

Interpretive Summary: The characterization of organic matter in agroecosystems is important due to its involvement in many soil ecosystem processes. To investigate the effects of tillage, cropping system, and N source, labile water-extractable organic matter and refractory pools of soil organic matter(i. e. humic and fulvic acid) were extracted from soils collected from nine-year agroecosystem study fields, and characterized using multi-dimensional fluorescence spectroscopy with parallel factor analysis. The three treatment factors (tillage, cropping, and N source) did not affect the fluorescence-relevant component distribution of the refractory soil organic matter fractions. But, the fluorescence-relevant components in the labile water-extractable organic matter fraction were significantly affected by the N source treatment. The results of this study support the use of fluorescence technique as a method to monitor the dynamics and chemical nature of soil organic matter pools. In addition, this study clearly suggests that the labile water-extractable organic matter pool should be the focus of studies investigating how soil management practices affect the short-term chemical properties of soil organic matter.

Technical Abstract: The characterization of organic matter in agroecosystems is important due to its involvement in many soil ecosystem processes. Humic acid, fulvic acid, and water-extractable organic matter from a nine-year agroecosystem study investigating the effects of tillage, cropping system, and N source were characterized using multi-dimensional fluorescence spectroscopy with parallel factor analysis (PARAFAC). The fluorescence spectra suite containing all three types of organic matter fractions was modeled by five PARAFAC components. The distribution of component concentrations was unique to each type of organic matter fraction, indicating that they reflect differing chemical pools of soil organic matter. The three treatment factors (tillage, cropping, and N source) investigated in this study did not affect the component distribution of the humic and fulvic acid fractions which are regarded as the refractory pools of soil organic matter. In contrast, the component distribution of the more labile water-extractable organic matter fraction was significantly affected by the N source treatment. The results of this study support the use of multi-dimensional fluorescence spectroscopy with PARAFAC as a method to monitor the dynamics and chemical nature of soil organic matter pools. In addition, this study clearly suggests that the labile water-extractable organic matter pool should be the focus of studies investigating how soil management practices affect the short-term chemical properties of soil organic matter.

Last Modified: 4/18/2014
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