Soil Carbohydrate Composition: Use in the Study of Soil Organic Matter Quality and Dynamics. (3743)
Authors:
D.A. Angers* - AAFC
M.H. Chantigny - AAFC, Ste. Foy, QC P. Rochette - AAFC, Ste. Foy, QC
Abstract:
Carbohydrates represent approx. 15-25% of soil organic matter. They are complex polymers of plant and microbial origin. Acid hydrolysis followed by either liquid or gas chromatography allow for the identification and quantification of the monomers which compose these polymers. Both neutral and amino sugars have been used to study the fate of organic residues, to identify the origin of soil carbohydrates, and to study their role in soil aggregation. The analysis of neutral sugar composition has shown the progressive accumulation of microbially-derived sugars during the decomposition of plant residues. Stable soil aggregates contain more microbial carbohydrates that non-aggregated soil. The study of amino-sugars has shown that cultivation of native grassland or forest leads to a reduction in the fungal population relative to bacteria. Similarly, no-till soils usually show greater relative proportions of fungal vs. bacterial amino-sugars. Close relationships are also observed between fungal glucosamine and soil aggregation. Detailed soil aggregate fractionation suggests that the preferential accumulation of fungal-derived C in NT soils could be due to the role that fungi play in the binding of microaggregates into
macroaggregates.
Speaker Information: Denis Angers, AAFC, Research Centre 2560 Hochelaga Blvd., Ste. Foy, QC G1V 2J3; Phone: 418 657 7980; E-mail: [email protected]
Session Information: Wednesday, November 3, 2004, 7:55 AM-12:00 PM Presentation Start: 11:20 AM
