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Warren, Steven D

Cyanobacteria were immobilized on hemp cloth, which was subsequently cut into fine pieces for use as a soil amendment. The amendment is intended for speeding recovery of microbiotic soil crusts in semi-arid and arid lands where such crusts have been destroyed by anthropogenic activities. Microcoleus vaginatus, Schizothrix calcicola, and Nostoc were used to create amendments, but most of the experiments in this study utilized the Microcoleus amendment, as it is the most cosmopolitan and ecologically important cyanobacterial taxon in desert soil crusts. The amendment was found to retain its viability in storage for at least 18 months. M. vaginatus grew best in CT and Z8+ (plus vitamins) media with aeration and addition...
Biological soil crusts of arid and semiarid lands contribute significantly to ecosystem stability by means of soil stabilization, nitrogen fixation, and improved growth and establishment of vascular plant species. In this study, we examined growth and nutrient content of Bromus tectorum, Elymus elymoides, Gaillardia pulchella, and Sphaeralcea munroana grown in soil amended with one of three levels of biological soil crust material: (1) a low-fertility sand collected near Moab, Utah; (2) sand amended with a 1-cm top layer of excised soil crust; and (3) crushed crust material. In addition, all plants were inoculated with spores of the arbuscular mycorrhizal fungus, Glomus intraradices. Plants were harvested after...
Cryptobiotic soil crusts are an important component of semiarid and arid ecosystems. An important role of these crusts is the contribution of fixed nitrogen to cold-desert ecosystems. This study examines the residual effects of various intensities and combinations of different surface disturbances (raking, scalping, and tracked vehicles) on nitrogenase activity, chlorophyll content, and chlorophyll degradation in these soil crusts. Nine months after disturbance chlorophyll content of disturbed soils was not statistically different from undisturbed controls, except in the scalped treatments, indicating recovery of this characteristic is fairly quick unless surface material is removed. Differences in chlorophyll degradation...
A growing body of evidence indicates that biological soil crusts of arid and semiarid lands contribute significantly to ecosystem stability by means of soil stabilization, nitrogen fixation, and improved growth and establishment of vascular plant species. In this study, we examined growth and mineral content of Bromus tectorum, Elymus elymoides, Gaillardia pulchella, and Sphaeralcea munroana grown in soil amended with one of three levels of biological soil crust material: (1) a low-fertility sand collected near Moab, UT, (2) sand amended with a 1-cm top layer of excised soil crust, and (3) crushed-crust material. Plants were harvested after 10 weeks growth, dried, weighed, and leaves were ground for nutrient analysis....
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