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EFFECTS OF FERTILIZER TYPE (CHICKEN LITTER VS. INORGANIC FERTILIZER) AND CATTLE GRAZING ON THE SOIL MICROBIAL COMMUNITY
Citation:
Kisselle, K., R G. Zepp, M Molina, R A. Burke Jr., AND A. J. Franzluebbers. EFFECTS OF FERTILIZER TYPE (CHICKEN LITTER VS. INORGANIC FERTILIZER) AND CATTLE GRAZING ON THE SOIL MICROBIAL COMMUNITY. Presented at 2003 Annual Symposium: Soil Biodiversity and Function, Lancaster, United Kingdom, March 25-27, 2003.
Impact/Purpose:
The overall objective of this task is to develop quantitative relationships for assessing the vulnerability of aquatic resources to global change. The task will contribute experimental and modeling tools for assessments of the interactions of global climate and UV changes with coral reefs and selected watersheds and estuaries in the U.S. These activities are contributing primarily to two APGs in the ecosystems component of the Global Change Research Multiyear Plan: the 2006 APG (APG 3) on building the capacity to assess global change impacts on coastal aquatic ecosystems, including coral reefs and estuaries and the 2004 APG (APG 2) on building capacity to assess and respond to global change impacts on selected watersheds. One major task objective is to assess interactions of global warming and UV exposure that are contributing to the observed coral bleaching and disease. Our lab is working with scientists at the NHEERL Gulf Ecology Lab to characterize UV exposure and effects at several coral reef sites. Other research in this task is examining the interactions between UV-induced breakdown of refractory organic matter in estuaries and coastal areas that enhance UV penetration into the water and concurrently form biologically-labile nitrogen-, phosphorus- and carbon-containing substances that stimulate productivity and microbial activity. This task also involves research in central Brazil that is part of the Large Scale Biosphere Atmosphere Experiment (LBA). The objectives of this project are to assess the impacts of land use and climatic changes on soil nutrient cycles and microbiota, trace gas exchange and water quality in the Brazilian cerrado. This work involves a close collaboration between EPA and a group of scientists from the Department of Ecology, University of Brasilia, Brazil. Other objectives of this task are to assess the interactions of land use and climate changes with the ecological functioning of streams in watersheds of the Piedmont region of the southestern U.S.
Description:
Pasture plots included unharvested, hayed, light and heavy cattle grazing pressure, fertilized with either inorganic N-P-K or broiler litter. Total phospholipid fatty acids (PLFAs) followed a seasonal trend and were higher in grazed plots than hayed & unharvested plots. Fungi and protozoa made up a larger percentage of the microbial community during the growing season, while bacteria and actinomycetes made up more in the autumn samples. Broiler litter plots had less fungi and slightly more bacteria and actinomycetes than plots receiving inorganic fertilizer. The hayed treatment had higher quantities of protozoan PLFAs and smaller quantities of bacterial PLFAs. Indirect evidence of top-down control of bacterial populations in all plots is given by a significant inverse relationship between a protozoan PLFA and the sum of several bacterial PLFAs.