ARS | Publication request: ENVIRONMENTAL CONTROLS ON BIODIVERSITY OF SOIL MICROBES

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: May 13, 1999
Publication Date: N/A

Technical Abstract: Microbial populations in soil form communities that could vary in composition and structure depending on the abiotic (temperature and water regimes) and biotic (plant-microbe associations) factors present. Experiment 1: Matric potential was adjusted to -0.03 and -0.3 Mpa. Experiment 2: Soil was incubated at 22 and 34 C. Bulk and rhizosphere soil from soybean plants were sampled at 5 and 15 days after planting. Experiment 3: Soil under tall fescue (Festuca arundinacea) plants either infected or not by the fungus Neotyphodium coenophialum was collected at different soil depths. In all experiments, soil microbial populations were studied by whole soil fatty acid methyl ester technique (whole soil FAMEs). Temperature had no apparent effect on the whole soil profiles in either bulk or rhizosphere soil. Matric potential had no effect on FAME profiles from bulk soil, but did affect FAME profiles from rhizosphere soil. Endophyte infection caused small differences in FAME profiles mainly at th soil surface. Detection of microbial biodiversity remains a challenge because of the presence in soil of microhabitats and the lack of identification of 100% of the microbes present. Fatty-acid methyl esters offer a promising approximation of microbial diversity.