Assessing GHG mitigation options for crops at regional level using ecosystem modelling and LCA
Résumé
Soil, climate and management practices make greenhouse gas (GHG) emission estimates associated with crop production highly uncertain. Biophysical modelling provides reliable reactive nitrogen (Nr) estimates for environmental assessment. In this paper LCA and ecosystem modelling are combined to improve GHG estimation from cropping systems in the Paris (France) area, and to compare environmental impacts of two cropping systems at regional level. A cropping system aimed at productivity with high environmental performance (PHEP), while the other one aimed to reduce (GHG) emissions by half (50%GHG). Model-derived GHG estimates for crop production were at least 7% lower than estimates from the standard methodology applied to LCA, emphasizing the importance of regional factors in agricultural LCAs. The 50%GHG cropping system appears promising (184% reduction in the life-cycle GHG emissions) for climate mitigation of arable crops, pending trade-offs with other impact categories.