Monday, November 5, 2007
99-13

The Denitifier Community after a Century of Turf Management.

Emily Dell1, Thomas Rufty2, Daniel Bowman3, and Wei Shi2. (1) Soil Science, North Carolina State University, Campus box 7619, Raleigh, NC 27695-7619, (2) North Carolina State University, Dept of Soil Science, NC State University, Raleigh, NC 27695-7619, (3) Williams Hall 4123, Box 7620, North Carolina State University, North Carolina State University, Dept. of Crop & Soil Science, Raleigh, NC 27695

Denitrifiers are agronomically and environmentally important bacteria. By cycling soil nitrate to atmospheric nitrogen, denitrifiers remove nitrogen from soil systems. In addition, greenhouse gases such as nitric oxide and nitrous oxide are released during the denitrification process. The denitrifier population was examined in a series of golf courses 1, 6, 23, and 95 years old using denaturing gradient gel electrophoresis (DGGE) and the sequencing of nirK and nosZ gene fragments in order to detect affects of long-term turf management on the denitrifier community structure. Analysis of DGGE fingerprints showed a greater difference between the adjacent natural environment (pine) and turf than among turf of different ages. However, phylogenetic analysis of clones for both functional genes showed that older turfs (23 and 95 yrs) were more similar to each other than to younger turf (1 yr). Richness, as measured by rarefaction analysis, did not change among turf sites for nirK clones but decreased in older turfs for nosZ clones. Overall, results indicate that long-term management indeed affected community structure of denitrifiers in turf grass.