Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: July 28, 2004
Publication Date: October 31, 2004
Citation: Nichols, K.A., Berdahl, J.D. 2004. Changes in aggregate stability and glomalin concentration in grass and forage nursery plots. ASA-CSSA-SSSA Annual Meeting Abstracts. Technical Abstract: Grass and forage nursery plots have been established at two locations at the Northern Great Plains Research Laboratory in Mandan, ND on an annual basis from 1987 to 2002. Plant species grown in these plots include: Russian Wildrye, Intermediate Wheatgrass, Crested Wheatgrass, Western Wheatgrass, Alfalfa, Blue Grama, Switchgrass, Big Bluestem, and Indiangrass. Mycorrhizal fungi are associated with all of these plants, but the degree of association varies from facultative to obligate. Glomalin is a glycoproteinaceous substance produced on hyphae of mycorrhizal fungi. This substance is thought to help protect hyphae from desiccation while at the same time provide a sticky surface to hyphae where organic matter and debris in the soil may collect and begin to form soil aggregates. The sugars in the glomalin molecule provide the glue, while hydrophobic amino acids create a water-insoluble protective barrier to fungal hyphae and soil aggregates. In a monoculture system, such as that found in the nursery plots, the degree of mycorrhizal association with the host plant affects the amount of glomalin accumulating in these soils and the aggregate stability of these soils. Well-structured soil, possessing a large number of water-stable aggregates, has improved water infiltration, aeration, nutrient cycling, and plant health (which improves forage quality, biomass, and carbon sequestration).