Submitted to: American Society of Agronomy Branch Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 5/25/2004
Publication Date: 6/30/2004
Citation: Weaver, M.A., Zablotowicz, R.M., Bryson, C.T. 2004. Soil microbial community responses to hydrology and vegetation in a mississippi delta forested riparian zone. [Abstract]. American Society of Agronomy Branch Meeting.
Technical Abstract: Riparian buffer zones are highly productive ecotones, critical in protecting downstream systems from upstream sources of nutrients, pesticides, and sediments. Soil properties, enzyme activities, microbial fatty acid composition and plant species composition were assessed in a riparian corridor between cropland and Beasley Lake, in Sunflower County, Mississippi. This riparian corridor spans several gradients: from a heavily wooded, typical bottomland hardwood forest above the channel, to an open-area assemblage of annual and perennial, facultative hydrophytic vegetation lower in the system. The soils in this system form a gradient with more sand and less clay (mean = 18% sand, 39% clay) on the forested banks compared to the channel (mean = 7% sand, 59% clay). Coinciding with the differences in vegetation, hydrology and soil type were significant differences in the microbial community structure and activity. Fluorescein diacetate hydrolysis and triphenyl tetrazolium chloride dehydrogenase activities were and positively associated with each other and with clay content, but did not vary with stream or slope position. The microbial community, as assessed by Fatty Acid Methyl Esters (FAME), significantly responded to slope position, sampling date and soil textural components, but not to stream position. The interactions between vegetation, soil properties and the microbial community are being studied to better understand their cumulative role in effective contaminant removal by riparian zones.