Regionalised modelling of recycled fertiliser P in agricultural fields:Development of the life cycle inventory model PLCI 2.0

Phosphorus (P) in societal waste streams can be recycled and used as recycled P fertilisers (RPFs). When developing new technologies for P recycling, life cycle assessment (LCA) can be used to assess their environmental impact and support environmentally friendly decisions. In LCA calculations, inventory factors describe, for example, the emissions, resource requirements and potential substitution of products. The Phosphorus Life Cycle Inventory (PLCI) model is a tool for estimating such inventory factors for the use of RPFs. The main objective of this study was to develop the PLCI model from its previous parameterisation for Denmark to make it applicable to all countries and regions of the EU. This was undertaken by considering parameters that describe regional conditions affecting the loss of P, crop P uptake and potential mineral fertiliser substitution. Such parameters include soil type, soil P status, soil erosion, groundwater leaching, crop types, productivity and crop P concentrations. Several RPFs were incorporated into the model, including coefficients describing the partitioning to the labile, plant-available P fraction. To illustrate the applicability of the model, a case study was performed. Applications of RPFs were modelled in the Copenhagen region in Denmark and the Piedmont region in Italy. The higher soil erosion rate in Piedmont resulted in over six times greater P loss than in Copenhagen. The difference in P fertilisation practice between the regions had a strong impact on the mineral fertiliser substitutions. The results point to the importance of defining the fertilisation regime of the region being modelled, and this is now possible with the new, more dynamic version of PLCI. In conclusion, the new PLCI 2.0 model provides a dynamic tool for LCA practitioners to estimate region-specific inventory factors for RPFs. The model is relatively easy to use and captures differences between fertilisers with varying P availability and between applications in different regions of the EU.