Phosphorus (P) is an essential element for all living organisms, and at the current rate of extraction, global reserves will be exhausted in the next few centuries. Often, P balances calculated for organically managed arable systems indicate that more P is removed with the products than applied as fertilizer. Within the IMPROVE-P consortium, the relative P fertilizer effectiveness of most recycling P fertilizers was assessed. Most organic P fertilizers with exception of meat and bone meal have a relatively high relative P effectiveness. Struvite obtained from chemical approaches for P recycling also showed high P effectiveness, while incineration and most other thermal approaches downgraded the final fertilizer value by the loss of organic matter, nitrogen and sulfur, and by reducing the P fertilizer efficiency. The suitability of recycling P fertilizers as P source is largely dependent on the soil reaction
