The new regulations of the German Fertiliser Ordinance mean that the use of farm fertilisers is becoming more important. The declaration of goods (labelling) is becoming important for donors/importers to comply with the provisions of the Fertiliser Ordinance in addition to the other requirements. The procedures for recycling or upcycling of farm fertilisers are manifold; it remains to be seen whether these procedures can already be implemented in practice and which requirements must be met.
Based on the example of the Witte plant (upgrading manure through composting), related to readiness for marketing, economic efficiency, legal framework conditions, robustness of the composting technology, this technology was thoroughly examined. In addition to the strengths and weaknesses of the method, opportunities and implementation associated with the possibility were discussed. The Witte plant as a technology was assessed as innovative, but to solve the entire problem of fertiliser surplus in some regions of Germany by means of this approach was regarded as an impossible task. The Witte plant can be one of many solutions and is rather a partial solution of the whole problem.
The main risks are costs for logistics, registrations, absorption limits and the formulation of the definition of fertiliser, waste or soil. The entire value chain could benefit from these solutions. All parties involved agreed on this and continue to see many adjusting screws for the reduction of nutrient inputs in the future.
For further work additional expertise is needed. Since there cannot be a single solution for this general problem, support of additional experts, practitioners and politicians is needed.
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