Sensitivity analysis of WUM for calculating mineral excretion : evaluation of variation in starting values of WUM model on the excretion of nitrogen (N), phosphorus (P) and total potential ammonia nitrogen (TAN) from farm animals in the Netherlands

This project focuses on improving the substantiation, transparency and quantification of the accuracy of the calculation of nitrogen (N), phosphorus (P) and total potential ammoniacal nitrogen (TAN) excretion by WUM (in Dutch: Werkgroep Uniformering berekening Mest- en mineralencijfers). The first step in this project is to assess the sensitivity of the N, P and TAN excretion to variation in the WUM model input. A single input parameter change of 10% was simulated in seven different scenarios, while all other input parameters were kept constant. Based on the results of this sensitivity analysis and of the uncertainty analysis performed earlier, and the contribution to the overall TAN excretion, topics for further research were defined and prioritized.