ARS | Publication request: On-site wood-chip bioreactors could reduce indirect nitrous oxide emissions from tile drain waters

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: February 10, 2011
Publication Date: February 15, 2011
Citation: Fujinuma, R., Venterea, R.T., Ranaivoson, A., Moncrief, J., Dittrich, M. 2011. On-site wood-chip bioreactors could reduce indirect nitrous oxide emissions from tile drain waters [abstract]. Proceedings of Nutrient Efficiency and Management Conference. MN Department of Agriculture. February 15, 2011. Abstract #5.

Technical Abstract: Indirect nitrous oxide (N2O) emissions originating from nitrate-laden agricultural drainage waters represent approximately 21% of total N2O emissions in the USA. Typical strategies to mitigate indirect N2O emissions are either improving fertilization methods or on-site treatment of drainage water. Recently, wood-chip bioreactors have been shown to reduce nitrate in drainage waters. However, no field studies have evaluated balances between nitrate removal and release of dissolved N2O by on-site wood-chip bioreactors. We measured nitrate-N, dissolved N2O-N, and flow rates of bioreactors in two locations (Dundas, and Claremont, Minnesota, USA) during the 2010 growing season. Drainage waters contained an average of 24 and 16 mg N L-1 of nitrate, and 21 and 9 µg N L-1 of N2O-N in Dundas and Claremont, respectively. Bioreactors reduced nitrate-N concentration in both locations (22-99% in Dundas, 6-77% in Claremont). However, bioreactors reduced N2O-N concentration only in Dundas (average 64%), not in Claremont (increased 21 times). Results indicated that on-site wood-chip bioreactors could mitigate indirect N2O emissions if hydraulic residence time is long enough, and denitrification process goes to completion, i.e., from NO3 to N2.