Infodoc : Sciences, Techniques et Culture

Agriculture interacts with a range of environmental issues, including global warming. The environmental impacts of agriculture are highly dependent on soil and climate conditions, and may be quantified with life cycle assessment (LCA). The variability of emissions related to the dynamics of C and reactive forms of N at the field scale results in large uncertainties for LCA of agricultural systems. Estimations of theses emissions may be realised using agroecosystem models. Approaches combining models and LCA to assess cropping systems are scant and have only involved simple cropping systems so far. In this dissertation I combined LCA and agro-ecosystem models (in particular CERES-EGC) to assess cropping systems. To evaluate the accuracy and reliability of models results, emissions were[...]

Agriculture interacts with a range of environmental issues, including global warming. The environmental impacts of agriculture are highly dependent on soil and climate conditions, and may be quantified with life cycle assessment (LCA). The variability of emissions related to the dynamics of C and reactive forms of N at the field scale results in large uncertainties for LCA of agricultural systems. Estimations of theses emissions may be realised using agroecosystem models. Approaches combining models and LCA to assess cropping systems are scant and have only involved simple cropping systems so far. In this dissertation I combined LCA and agro-ecosystem models (in particular CERES-EGC) to assess cropping systems. To evaluate the accuracy and reliability of models results, emissions were measured in two fiels trials : ICC (Innovative cropping systems under Constraints) and CIMAS (Conventional versus Integrated Management Agricultural Systems) with different climatic and soil conditions. Another data set was used to compare N2O observations with model predictions on an daily time step (Nitroeurope trial). When applied to the ICC trial, CERES-EGC revealed a 29% difference in N2O between a cropping system aiming at halving GHG emissions overall, and a reference system close to current practice, with good predictions considering the large variability in measured N2O emissions. [...]