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Title: CHANGES IN AGGREGATE STABILITY AND CONCENTRATION OF GLOMALIN DURING TRANSITION FROM PLOW TO NO TILLAGE MANAGEMENT

Author
item Wright, Sara
item Starr, James
item PALTINEAU, IOAN - UNIV. OF MARYLAND

Submitted to: Soil Science Society of America Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/15/1999
Publication Date: N/A
Citation: N/A

Interpretive Summary: A recent discovery of copious production of an unusually stable protein by a ubiquitous group of beneficial soil fungi has started a cascade of discoveries into the function of this protein in soil stabilization. The protein was named glomalin. Glomalin is a glue that holds primary soil particles together in water stable aggregates. A visible indicator of soil health is the quantity and stability of aggregates. Fungi that produce glomalin function better when they are not disturbed by plowing. The current experiment shows the build up of aggregate stability and glomalin over three years of no-till management of corn compared to plow-tilled management. This is the first report of glomalin build-up in no-till management of cropped land and will lead to better management practices to maintain or enhance soil structural stability. The impact will be preservation of agricultural soils for current and future generations

Technical Abstract: Improvement in structure of degraded soils or prevention of degradation of structure in healthy soils requires an understanding of processes contributing to aggregate stability. The impact of cropping systems on molecules produced by soil microorganisms that contribute to aggregate stability is part of the process that has not been elucidated. The relationship between aggregate stability and glomalin, a glycoprotein produced by arbuscular-mycorrhizal (AM) fungi, was studied during the first three years in transition from plow tillage (PT) to no tillage (NT) on maize. Results showed a high correlation between glomalin concentration in aggregates and aggregate stability. Increases in both aggregate stability and glomalin were measurable from year-to-year in NT plots, but differences were significantly higher (p<0.05) than PT plots only after two or three years. Comparison of NT plots after three years with nearby soil in grass cover indicated that there was still a 20% greater stability and 45% highe concentration of glomalin in the grass-covered soil. Comparison of PT and NT (3 year) interrow samples with intrarow samples indicated that plant roots and NT management may have a synergistic effect on aggregate stabilization. These results show that cropping systems should be evaluated for the impact on production of glomalin by AM fungi.