Measurement and Modelling of Denitrification in the Shallow
Groundwater of Hydromorphic Soils for Estimating Actual and Long-term Nitrate Reduction and Nitrous Oxide Emission.
(4402)
Authors:
R. Well* - Institute of Soil Science and Forest Nutrition Goettingen H. Hoeper - Geological Survey of Lower Saxony, Bremen
O. Mehranfar - Institute of Soil Science, Goettingen
Abstract:
Denitrification capacity (Dcap), long-term denitrification potential (LDP) and N2O production was measured in 585 samples from the saturated zone of 18 hydromorphic soils by anaerobic incubation of K15NO3 amended slurries in the laboratory and analyzing N2O and 15N2+15N2O in the sample headspace. Texture, pH, carbon fractions, total nitrogen and sulfide were measured in order to model Dcap by multiple regression analysis. Mean Dcap of the substrate groups sand, loam and peat was 0.13, 1.34 and 26.6 mg N kg-1 d-1, respectively. Regression models for predicting Dcap were found to be suitable to estimate mean Dcap of sites of medium or high activity, but prediction for individual samples and for means of sites with low activity was unsatisfactory. The N2O-to-N2+N2O ratio was highly variable and was poorly correlated with soil properties except for pH. LDP as determined from cumulative nitrate reduction during 500 days of anaerobic incubation was highly correlated with Dcap and ranged between 40 and 170 mg N kg-1 and between 110 and 1560 mg N kg-1 in the sandy and loamy sites, respectively.
Speaker Information: Reinhard Well, Institute of Soil Science and Forest Nutrition Goe, Institute of Soil Science and Forest Nutrition,University of Goettingen, Buesgenweg 2, Goettingen, 37077; Phone:
+49551395507; E-mail: [email protected]
Session Information: Wednesday, November 3, 2004, 10:00 AM-12:00 PM Presentation Start: 10:00 AM (Poster Board Number: 1750)
Keywords: denitrification; hydromorphic soil; nitrate; modeling