|Venterea, Rodney - Rod|
|RANAIVOSON, ANDRY - University Of Minnesota|
|MONCRIEF, JOHN - University Of Minnesota|
|DITTRICH, MARK - Minnesota Department Of Agriculture|
Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 5/1/2010
Publication Date: 10/31/2010
Citation: Fujinuma, R., Venterea, R.T., Ranaivoson, A., Moncrief, J., Dittrich, M.A. 2010. Mitigating Sources of Indirect Nitrous Oxide Emissions from Tile Drain by On-Site Wood-Chip Bioreactors [abstract]. ASA-CSSA-SSSA Annual Meeting Abstracts. Paper No. 652.
Technical Abstract: Indirect nitrous oxide (N2O) emissions originating from nitrate-laden agricultural drainage waters represent a substantial fraction 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 a growing season. Drainage waters contained an average of 24 and 16 mg N L-1 of nitrate in Dundas and Claremont, respectively. Bioreactors reduced nitrate-N concentration in both locations (22-99% in Dundas, 6-77% in Claremont). Drainage waters contained an average of 21 and 9 µg N L-1 of N2O-N in Dundas and Claremont, respectively. Ratios of dissolved N2O-N to NO3-N in inflow of bioreactors were were consistent with published data (0.0003-0.06). Bioreactor treatments reduced dissolved N2O concentration in Dundas (average 64%), but increased in Claremont (average 21 times). Using indirect N2O emission factors (EF5) by Intergovernmental Panel on Climate Change, the bioreactor in Dundas was estimated to mitigate 14 g N ha-1 of indirect N2O emissions. In contrast, the bioreactor in Claremont was estimated to increase indirect N2O emissions. Results indicated that on-site wood-chip bioreactors could mitigate indirect N2O emissions if hydraulic residence time is long enough.