1. JRC-AL: 24.11.2010 – NE-C5-Wageningen - 1 Stratification of N2O fertiliser- induces emission factors (FIE) - Methods → DNDC-EUROPE simulation on ca. 200,000 spatial units (HSMUs) → Up to 3 crops/HSMU (simulation entity) Minimum 10% of UAAR in HSMU → Each simulation entity 10 simulations with different meteorological years (1991-2000) identical initialization (15 years spin-up 1976-1990) → Determination of fertiliser-induced emission factors (FIE) for Mineral fertilisers: default manure input, variation of mineral fertiliser input around default application rate: ±10%; ±25%; 50%; 0%. Manure: idem. → FIEs are evaluated By country For input of mineral fertilizer and manure nitrogen For mineral and organic soils (three SOC levels of mineral soils: <1%, 1-3%, 3-12% ) Leip et al. (Env Poll. accepted)

2. JRC-AL: 24.11.2010 – NE-C5-Wageningen - 2 Default scenarioMeanMedianLowHighn All mineral soils3.71.80.1422.11 240 306 Low SOC1.00.60.094.4190 850 Medium SOC2.31.40.1612.3652 446 High SOC7.24.40.5337.2397 010 Impact of SOC on N2O fluxes Data in [kg N 2 O-N ha -1 yr -1 ], Leip et al. (Env Poll. accepted)

3. JRC-AL: 24.11.2010 – NE-C5-Wageningen - 3 Temporal variation of FIEs for EU25 → For EU25, FIEs are relatively constant in time → High spatial variability observed both in measured and simulated N2O fluxes does not translate in an equally high uncertainty of national or supra-national emission factors. → For EU25 a single emission factor (close to IPCC default) for N2O fluxes gives reasonable results. FIEminFIEman 19901.01%1.09% 19911.02%1.13% 19921.12%1.38% 19931.20%1.26% 19941.14%1.50% 19951.03%1.25% 19961.25%1.01% 19971.21%1.36% 19981.13%1.24% 19991.31%1.46% 20001.23%1.15% all years1.15%1.26%

4. JRC-AL: 24.11.2010 – NE-C5-Wageningen - 4 Temporal variation of FIEs at country scale mean summer temperature summer precipitation

5. JRC-AL: 24.11.2010 – NE-C5-Wageningen - 5 Average FIEs for EU25 at country- level minman BL1.2%0.9% DK0.6%1.3% DE1.7%2.6% GR0.7%1.2% ES0.6%1.0% FR0.9%1.1% IE1.1%0.7% IT0.8%1.5% NL1.7%1.5% AT1.5%1.0% PT1.0%2.3% SE2.1%1.1% FI3.0%0.7% UK0.5%0.4% minman CZ1.3%1.4% EE3.4%1.4% HU1.3%1.6% LT1.3%0.4% LV1.2%0.5% PL1.5%4.1% SI1.8%1.5% SK1.2%0.5% BG1.2%1.4% RO1.6%1.0% minmanall ave1.4%1.3% stdev0.7%0.8%0.7% min0.5%0.4% max3.4%4.1% EU251.15%1.26%1.17% → National inventories tend to overestimate the uncertainties in their estimated direct N2O emissions from arable soils → One national FIE for all countries not sufficient, sometimes large difference between FIE min and FIE man → There is still lack of observational data to provide robust national FIEs