1. A regional-scale soil phosphorus balance for exploring mineral fertilizer substitution potentials – the case of Norway Ola Stedje Hanserud 1,2, Eva Brod 1,3 and Helge Brattebø 2 1.Norwegian Institute for Agricultural and Environmnental research (Bioforsk) 2.Industrial Ecology Programme, Norwegian University of Science and Technology (NTNU) 3.Norwegian University of Life Sciences (NMBU)

2. Main objective Identifying the theoretical potentials for substituting mineral P fertilizer with P-rich waste sources, using Norway as a case study, disaggregated into its 19 counties

3. Method Substance flow analysis (SFA) Annual averages for 2009-2011 Main P flows to and from agricultural soil, converted to tons of P

4. National aggregate numbers

5. +

6. -637 -738 -443 -29 -262 -304 754 -2 6 -79 70 75 64 -105 -12 137 101 34 t P/yr Manure as only input

7. -637 -738 -443 -29 -262 -304 754 -2 6 -79 70 75 64 -105 -12 137 101 34 t P/yr Manure as only input

9. -637 -738 -443 -29 -262 -304 754 -2 6 -79 70 75 64 -105 -12 137 101 34 t P/yr Manure as only input 10 negative counties

10. -466 16 -300 77 -124 -161 1048 97 61 1 111 305 216 106 174 249 176 71 t P/yr Inputs: Manure Meat and bone meal Full wastewater potential 4 negative counties

11. Regional importance of wastewater P (tons P/yr) Inputs Output Animal manure Wastewater, potential Meat and bone meal Total withdrawal (yield + losses) Share wastewater of total withdrawal Norway12.00027003501340020 % Oslo & Akershus 27072030101071 % Sogn og Fjordane 7104036406 %

12. Assumptions Manure and wastewater P distributed within each county to substitute mineral P Balanced fertilization of crops (input = output) → overestimation of needed input 100% plant available P in meat and bone meal and manure

13. Wastewater P plant availability 1.Treatment method with certain treatment effect → total amount P in sludge 2.Total amount of P in sludge → plante available P given treatment method Treatment methodTreatment effect (%) 1 P-efficiency (%)* Chemical9015-35 (average: 25) 2 Biological30100 3 Chemical-biological9515-35 (average: 25) 2 Mechanic15100 * Compared to plant availability of mineral P fertilizer 1 Berge & Mellem 2012, 2 Øgaard 2013, 3 Krogstad et al. 2004

14. Quantification plant availability RegionTot-P in sludge (t/yr) Plant available P (t/yr) P-efficiency (%) North sea counties 143536025 Rest of the country 42515035 Whole country 186051027 Potential for mineral P substitution with todays technology:510 t P/yr Potential for mineral P substitution with new technology: 2700 t P/yr

15. Conclusions Regional soil P balances indicate substitution potentials Great theoretical potential in replacing mineral P fertilizer Plant availability of recovered wastewater P differs with technology/infrastructure Needs to be followed up with study of feasibility – Technical/economic/environmental – Social acceptability – Drivers (prices/costs, legislation, targets)