Soil-Concept contributed to the completion of the sub-project report on the production of ash fertilizer from sewage sludge. Furthermore, Soil-Concept contributed to the preparation for the spreading of the ash. This involved measurement results that could not be reproduced. The project partner Arvalis has received other measurement values regarding the P2O5 content from its measurement laboratory. It turned out that the measurement error was caused by the laboratory which had commissioned Soil-Concept. Now the measured values are comparable with those of Arvalis in one measurand and traceable. It remains to be seen how the ashes will show up in practical tests. The whole thing is delayed by the current circumstances.