PARENT SESSION
Poster Session 23: Soil Ecology
Wednesday, August 10, 5:00 PM - 6:30 PM, Exhibit Hall 220 A-E, Level 2, Palais des congrès de Montréal
Nitrogen fertilization triggers significant declines in AM fungal abundance-- A field study in ten weeks.
Bradley, Kate*,1, Drijber, Rhae2, Knops, Jean1, 1 University of Nebraska, School of Biological Sciences, Lincoln, NE2 University of Nebraska, Department of Agronomy and Horticulture, Lincoln, NE
ABSTRACT- We used fatty acid methyl esters (FAMEs) to measure the response of soil microorganisms associated with the mycotropic grass, Schizachyrium scoparium, to nitrogen (N) fertilization. Plots were sampled June 8 and fertilized June 9 with 0 g N/m2, 5.44 g N/m2, or 27.2 g N/m2. The plots were sampled 2, 4, and 10 weeks after the N fertilizer was applied. The major objectives of this study were to 1) compare the responses of microorganisms between N treatments using FAMEs and 2) to test the hypothesis that N fertilization can trigger changes in the microbial community before changes in the plant community are apparent. The FAME associated with arbuscular mycorrhizal fungi (AMF) exhibited the strongest response. Two weeks after the N treatments were applied the abundance of the AMF marker was significantly lower in the high N plots compared to the control plots. AMF levels remained significantly lower in the high N plots as compared to the other two treatments through the remaining sampling dates. Our results indicate that high rates anthropogenic N deposition can lead to significant changes in the abundance of ecologically important soil microorganism like AMF over short time periods, potentially disrupting the mutualistic relationship between plants and AMF.
Key words: AM fungi, nitrogen fertilization, mycorrhizae