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N 2. N 2 O. N 2 O. N 2. N 2 O. N 2. N 2 O. N 2. Danish Institute of Agricultural Sciences Department of Agroecology Research Centre Foulum. Denitrification in the root zone. Finn P. Vinther, Danish Institute of Agricultural Sciences, Department of Agroecology,
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N2 N2O N2O N2 N2O N2 N2O N2 Danish Institute of Agricultural Sciences Department of Agroecology Research Centre Foulum Denitrification in the root zone Finn P. Vinther, Danish Institute of Agricultural Sciences, Department of Agroecology, Research Centre Foulum
Denitrification NO3 N2O N2 (nitrate) (nitrous oxide) (atmospheric nitrogen) In the lab: Denitrification NO3 N2O N2 Acetylene Measuring denitrification In the field:
Measuring or modelling? • Resource demanding and difficult to measure • Modelling often the only possibility • Most models, however, often needs more input • information than what is available • Simple model for estimation of N2O emission • and denitrification – SimDen….. • which only needs information about • amount and type of added nitrogen • clay content of the soil
Fertilizer N2O emission Bouwman, 1996 Background N2O emission Principles of SimDen: Denitrification =N2O * (N2/N2O) Denitrification =N2O * (N2/N2O) Total N2O emission = Background N2O emission + EF1.25 * N-input Inorganic N: EF0.8 Organic N: EF2.5
WFPS* < 60% N2/N2O-ratio 0 - 3 60% < WFPS < 80% N2/N2O-ratio 3 - 5 WFPS > 80% N2/N2O-ratio 5 - 10 * Water filled pore space Principles of SimDen: Denitrification =N2O * (N2/N2O) Literature values (app. 500): Avg. N2/N2O-ratio: app. 3
SimDen Principles of SimDen: Denitrification Water filled pore space (WFPS) Soil texture (clay content)
How to use SimDen Example 1: Background denitrification
How to use SimDen Example 2: Background + fertilizer denitrification
How to use SimDen Example 3: Background + fertilizer denitrification at higher clay content
How does SimDen perform Danish studies
Canada (Paul & Zebarth, 1997) Spain (Vallejo et al., 2004) Sweden (Dahlin et al., 2005) The Netherlands (Zwart et al., 2004) How does SimDen perform Other studies
How does SimDen perform Other studies
How does SimDen perform Other studies
Herning How can SimDen be used? Regional mapping, as for example as shown here, where SimDen has been implemented into ”CT-tools”, ConTerra ApS, which use databases with information about soil types, fertiliser use, etc.
SimDen can be downloaded from www.agrsci.dk/simden Ending remarks • SimDen is based on average values, and the deni-trification is calculated for a climatically ‘normal’ year, or an average denitrification over years. • If more detailed estimates about the annual variation of the denitrification is wanted, dynamic models as for example Daisy must be used. • Wish you good luck and thank you for your attention!