1 Soil NO inventory from large scale farming in France: impact on atmospheric NO2 and O3 concentrations Achieved during 2 national French projects GICC et PNCA In Collaboration with : INRA (Grignon) : P. Laville, B. Gabrielle, A. L. Palluis LA (Toulouse): D. Serça, J. Cortinovis SA (Paris) : M. Beekmann, F. Ravetta INRA (Dijon) : C. Hénault

2 Grignon Auradé Dijon 1/ Field NO flux measurements (Auradé (32) and Grignon (78)) On Wheat, Maïs, Sunflower 2/Laboratory Measurements : soil incubations -> NO production according to the nitrification rate 3/ Development and validation of NO emission Model 4/ Achievement of NO soil inventory : impact on atmospheric pollution (Chimère)

3 Examples of In Situ Measurements : Auradé (Midi Pyrenees), Grignon (Ile de France) Annual Variations of NO flux : - Outside nitrogen input periods A background level ~ 1 à 3 gN-NO/ha/d - After nitrogen inputs largest NO emissions during 3 to 4 weeks -Largely dependent on : temperature- humidity – ammonia concentration of the soils Grignon

NO 3 - NO 2 - NH 4 + N 2 O, NO N2N2 Dénitrification (anaerobie) Nitrification (aerobie) Biological processes involved on N 2 O et NO productions K 1 (t ) K 3 (t ) K 2 (t) N 2 O(t) = K 1 (t) + K 2 (t) - K 3 (t) NO(t) = K’ 2 (t) NO K’ 2 (t)

5 NO emission model by nitrification process NO emission model by nitrification process NO = 2% VN VN = F N x F W x F T Simplified equation NO= AF.( Wp ). exp (Ln(2.1).T/10) 2% Km ~50

6 Examples of modeled NO fluxes using environmental soil inputs (Temperature, humidity, NH4)

7 Spatial and temporal Extrapolation of NO agricultural soil fluxes - Simplified version on NO emission algorithm (NH 4, Wp et T sol)- Simplified version on NO emission algorithm (NH 4, Wp et T sol) NO= AF.( Wp ). exp (Ln(2.1).T/10)NO= AF.( Wp ). exp (Ln(2.1).T/10) Nitrification rate = 10% [NH4]/jour (T= 10°C, Wp=20%) - Statistical survey on agricultural practices at regional scale :- Statistical survey on agricultural practices at regional scale : -> Distribution of arable land areas by crop types -> Dates et nitrogen quantity inputs for each type of crops => to set up a chronological function of nitrogen inputs according to the land use and to the agricultural practices

8 Survey on nitrogen use by crop and by region TAS 57% SAU TAS

9 Comparison between TAS et SAU for each regions SAU totale = km²TAS = km² (57% de la SAU)

10 Comparison between synthesis nitrogen deliveries (UNIFA) Comparison between synthesis nitrogen deliveries (UNIFA) And the amounts estimated according to our survey qté TAS =  N = millions tonnes (7%)TAS =57% de la SAU -2.4 millions tonnes of synthesis nitrogen fertilizers/year (65% in ammonia form) -1.4 millions tonnes of nitrogen manure /year

11 Steps to interpolate temporally the exogenous soil NH4 content N-NH 4 kg/ha. Oats in Ile de France. 3 1=start 1 st input.3=start 2 d input. 2=end 1 st input.4=end 2 d input. DOY Equiprobability of Inputs N1 (35 kg) et N2 (65 kg) during 21 days - during 21jours addition N1/21 et N2/21 - Nitrification of 10%/day - Area under function= N1+N2 35 kgN 65 kg

12 Chronology nitrogen inputs => time series of NH4 content in region A background level of 0.9 kg N-NH4/ha 115 kg/ha exogenous endogenous 59 kg/ha

13 Example of NO simulated fluxes obtained from the MM5 model outputs (T et Wp), and the temporal NH4 content time series Flux Grignon 2003

14 Yearly Balance of NO soil emissions in France

14.5 ktN-NO/year = 47.7 ktNO2/year on 57%SAU In rough approximation soil NO flux = 84ktNO2/year ~ 11% /transport and 5% / all sources (CITEPA) Methodology EMEP/CORINAIR=> EF = 0.7% (2.4MtN/an) =55.2ktNO2/an (Bouwman, 2002) Annually soil NO emissions

16 Impact on atmospheric chemistry (modeling with CHIMERE). Mean arable land NO emissions (June 2003) (Max 8 g N/ha/d) Additional O3 concentration linked to arable soil NO sources : mean estimates for June 2003 (max 3 ppb)

17 Conclusions Positive item : -Improvement in seasonal variation on NO Fluxes=> seasonal nitrogen inputs taken into account. - Parameterizations on NO flux versus soil humidity

18 Conclusions insufficient Item : No variability of emissions depending on soil type Only NO from nitrification is considered and the denitrification ? Emissions from animal manure were not study Variation of background [NH4] not take account (annually balance 0.5 ppm =>80% of fluxes) =>Simulate net mineralization And the other ecosystems or arable lands?