NOPOLU System2 Large scale assessment of non-point nutrient sources

Surplus model principles Statistics are available at administrative scale, often very aggregated, in any country Crops and livestock are grown / managed only on some type of land covers, crops and livestock types are under the Eurostat nomenclature, filters translate national nomenclatures. Relationships CLC types / land use are defined generally / locally Mixing both yields spatial disaggregation of statistics, thus making it possible to calculate non-point source contribution. Is a « statistically conceptual model »

Method of agricultural diffuse pollution evaluation with NOPOLU System2 Calculation of yearly surplus of Nitrogen & Phosphorus, … Desegregation of parameters from any NUTS level to any HYDROLOGIC level using a LAND COVER (CLC, remote sensing….) Spatial statistics for all rates Phenomenon modeled;  Symbiotic Fixation  Atmospheric deposition  Synthetic application fertilizers rates that can be modulate by organic fertilizer application  Volatilization of animals excreta in cattleshed, storing areas, pasture field,.. Basic Data  Agricultural activities census (crop, animals,…)  Land cover  G.I.S. layer, NUTS & sub-catchments topology

Results at level basin or NUTS Scenarios CLC Surpluses: Disaggregation method Disaggregation using soil coverage + Watersheds Limits Census at NUTS level

Livestock organic nitrogen output Whole France territory PostesQuantités (tonnes)Quantités / total excrété (%) N excrété total (bâtiments + pâturage) % Volatilisation total (selon hypothèses retenues) % N racine total (bâtiments + pâturage) % Bâtiments d’élevage N excrété % N épandu % N racine % Volatilisation (bâtiments) % Pâturage N excrété % N racine % Volatilisation (pâturage) %

Livestock organic nitrogen output in France

Livestock organic nitrogen source in France

Organic nitrogen spread on crop

Nitrogen sources Whole France Organic excreta from livestock: 1487 kt Synthetic fertilizer : kt Atmospheric deposition (EMEP 2000 source): 670 kt (surface CLC - 14 kg/ha/an), 430 kt (over arable land)

Symbiotic Fixation Symbiotic Fixation : 569 kt

Nitrogen sources following crop

Results : Surplus (1 255 kt - 42 kg/ha) & Bilan (932 kt - 31 kg/ha)

Result Maize fodder : bilan (129 kt - 93 kg/ha)

Results Maize fodder : Surplus (150 kt – 109 kg/ha)

Results Wheat : bilan (159 kt - 33 kg/ha)

Results : Wheat Surplus (1 255 kt - 42 kg/ha)

Results : bilan (932 kt - 31 kg/ha)

Results : Surplus (1 255 kt - 42 kg/ha

Transfer modelling Transfer modelling is be computed using:  Surplus values, slopes (at the sub-catchment level) and rainfall, flows, soil types determinants  Riverine loads calculation for calibration  Simple rules derived from physical processes. Model type is « empirical based on lumped physical equations »

Example, OSPAR (Fluxes results) Results from monitoring networks, used for other purposes as well Results from emissions assessments, itself fuelled by agricultural surpluses modelling

Pros & cons Transparent Separate processes Responsive to hypothesis Surplus checked on all EU countries Non circular referencing Easily implemented and run Transfer easily appreciated with enough statistical data Evolutive Detailed processes non modelled, especially following the « data- driven » concept Transfer model could be more process oriented Many processes still unknown or impossible to calibrate Too rough rate spatial variation can introduce strong border difference.