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Title: Evaluation of microbial populations, Rhizobium Trifolii, and endomycorrhizal associations in reclamation of surface mine spoils in Texas

The deficiency of nitrogen and phosphorus in mixed overburden mine spoils has resulted in interest in strategies to minimize fertilizer application. In this study, the abundance of microbial populations, with emphasis on those involved in nitrogen cycle transformations was estimated in variously aged spoils. Two beneficial plant-microbe associations, the clover-Rhizobium trifolii symbiosis and endomycorrhizal associations, were investigated in field and laboratory studies. While most groups of microorganisms regained pre-mining levels in revegetated spoils within 1.5 years after disturbance, algal populations were still reduced ten years after mining. Populations of nitrifying bacteria and asymbiotic nitrogen-fixing bacteria were as high in all spoils as in unmined soil. Indigenous populations of ineffective R. trifolii were present in spoil banks and older revegetated spoil. A laboratory study of survival of three commercial strains of R. trifolii for subterranean clover showed lethal effects of high temperature (45/sup 0/C) especially in moist spoil, and superior survival of strain 162X95. Endomycorrhizal associations, evaluated by assessment of root infection in bermudagrass, reached pre-mining levels by three to seven years after disturbance. Growth chamber studies to investigate the effects of the two symbiotic associations on subterranean clover in mine spoil at different fertility levels indicated that dual infection withmore » Rhizobium and VAM fungi was most beneficial for plant growth, nitrogen fixation, and nitrogen and phosphorus contents.« less
Authors:
Publication Date:
OSTI Identifier:
5777770
Resource Type:
Thesis/Dissertation
Resource Relation:
Other Information: Thesis (Ph. D.)
Publisher:
Texas A and M Univ.,College Station, TX
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; 54 ENVIRONMENTAL SCIENCES; RHIZOPUS; BIOLOGY; TEMPERATURE EFFECTS; SPOIL BANKS; LAND RECLAMATION; MYCORRHIZAS; NITROGEN CYCLE; NITROGEN FIXATION; OVERBURDEN; SURFACE MINING; TEXAS; FEDERAL REGION VI; FUNGI; MINING; NORTH AMERICA; PLANTS; USA 550700* -- Microbiology; 510500 -- Environment, Terrestrial-- Site Resource & Use Studies-- (-1989)