Submitted to: International Humic Substances Society Conference
Publication Type: Abstract Only
Publication Acceptance Date: June 21, 2002
Publication Date: June 21, 2002
Citation: NICHOLS, K.A., WRIGHT, S.E., SCHMIDT, W.F., CAVIGELLI, M.A., DZANTOR, K. CARBON CONTRIBUTION AND CHARACTERISTICS OF HUMIC ACID, FULVIC ACID, PARTICULATE ORGANIC MATTER AND GLOMALIN IN DIVERSE ECOSYSTEMS. IN: PROCEEDINGS OF HUMIC SUBSTANCES: NATURE'S MOST VERSATILE MATERIALS.INTERNATIONAL HUMIC SUBSTANCES SOCIETY. BOSTON, MA. 2002. PP 365-367.
Global climate change and soil carbon sequestration issues are entering the forefront of public policy, and emphasis is growing for research on carbon sinks and long-term terrestrial carbon stabilization. Humic acid (HA), fulvic acid (FA), humin and particulate organic matter (POM) have traditionally been studied because they were thought to comprised the majority of soil organic carbon (SOC) along with lesser inputs from microbial biomass and polysaccharide carbon. Although FA and HA and humin, in particular, are high in carbon and have long turnover times, they require a long time to form and are not easily managed. Glomalin, a ubiquitous and abundant glycoprotein produced by arbuscular mycorrhizal fungi, appears to be a major sink for SOC and accumulation may be managed through sustainable agricultural practices. Analysis of various soils throughout the US and the world shows that glomalin is present in large amounts (3 to 19 mg per g of soil). Studies were undertaken to define the products of various extraction sequences for HA and glomalin. Results showed that glomalin was a contaminant of both HA and humin. Knowledge of the presence of glomalin in HA and extraction methods to separate glomalin from these humic substances will aid in the structural analysis of glomalin, HA and humin. Glomalin is not only important as a short-term carbon sink but also in long-term stabilization of SOC by helping to form water-stable soil aggregates.