Modelling N2O emissions from organic fertilisers for LCA inventories

Summary

Apart from mineral fertilisers, organic fertilisers act mainly via the soil C-N pool in order to provide available nitrogen to plants. This different mode of action is not reflected so far in the current IPCC N2O emission model. Here we propose a simple model to calculate N2O emissions from organic fertilisers and plant residues. It considers the long-term immobilisation of N within stable organic matter in the soil as well as the mineralisation of additional N from the soil pool. A first test with field data showed reliable simulations of measured N2O emissions. By comparing values generated by our model with values generated by the IPCC model we show that the IPCC model may overestimate emissions from organic fertilisers. Therefore, within LCA inventories modelling of soil borne N2O emissions from organic fertilisers and crop residues should consider the different dynamics of N via the C-N pool in the soil.