We wish to thank the lab and field technicians of ILVO for their help during the composting trials， Directorate General for Research and Innovation，。

and partly executed within the FERTIPLUS project. The project FERTIPLUS (Grant Agreement No 289853) is co-funded by the European Commission， Theme 2—Biotechnologies， and to Antonio Quero Alba from PROININSO S.A. for providing the biochar based on holm oak. ， Agriculture Food. The views and opinions expressed in this paper are purely those of the writers and may not in any circumstances be regarded as stating an official position of the European Commission. We are grateful to Jos Arits and the Op de Beeck group for their logistic support， within the 7th Framework Programme of RTD， and for executing the chemical analyses. This research was partly financially supported by the Flemish Government - Sustainable Agricultural Development Division (ADLO)。