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Nitrogen Fixation In Arid Western Soils, Robert Charles Rychert

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Nitrogen fixation by blue-green algae-lichen crusts from South Curlew Valley, Utah, in the Great Basin Desert, was studied using the acetylene reduction technique. A molar ratio of 3 moles C₂H₄ produced/mole of N₂ fixed was used to estimate nitrogen (N₂) fixation by acetylene reduction. Nostoc was found to be present in many of the lichen thalli examined microscopically. Crust nitrogen fixation decreased rapidly below -1/3 bar pressure (water potential) which indicated that nitrogen fixation occurs only when the crust is wet. This would suggest that most of the crust nitrogen fixation in the Great …