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Title: STIMULATION OF DENITRIFICATION AND NITRATE REMOVAL FROM SUBSURFACE DRAINAGE WATER

Author
item Moorman, Thomas
item Parkin, Timothy
item Jaynes, Dan
item Kaspar, Thomas

Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 11/6/2003
Publication Date: 11/16/2003
Citation: MOORMAN, T.B., PARKIN, T.B., JAYNES, D.B., KASPAR, T.C. STIMULATION OF DENITRIFICATION AND NITRATE REMOVAL FROM SUBSURFACE DRAINAGE WATER. ASA-CSSA-SSSA ANNUAL MEETING ABSTRACTS. 2003. CD-ROM. MADISON, WI.

Interpretive Summary:

Technical Abstract: Nitrate in subsurface (tile) drainage from corn and soybean fields is an important source contributing to excessive stream nitrate concentrations. Field and laboratory studies assessed the performance of wood chips as a carbon source for a denitrification wall. Drainage lines in the center of the plots led to equipment for measurement of flow and sampling. Wood was placed in trenches parallel to drain lines to intercept water and nitrate. Soybeans without N fertilizer were grown in 2001 and corn with N fertilizer was grown in 2002. Mean nitrate concentrations were reduced by the wood chip denitrification wall, but drainage volume was not affected, compared to the control plots. In 2001 the N loss was reduced from 70 to 20 kg N/ha by the denitrification wall. In 2002, N loss was reduced from 51 to 18 kg N/ha by the wall. Laboratory experiments with 15N-NO3 showed that microbial immobilization of N by microorganisms was not a significant N removal mechanism. After two years in the field, 11 to 34% of the wood was decomposed, with decomposition proceeding more slowly deeper in the soil. Short-term denitrification rates (nitrate and acetylene amended soil slurries) for the the wood chips were between 14 to 390 times greater denitrification activity than for the subsoils at similar depths. Results from 2003 will also be presented.