In the Baltic Sea pilot, three biobased fertilizers (BBFs) such as granules, foliar spray and vermicompost have been formulated through bokashi fermentation of fish waste, HORECA waste, tree leaves and wood burning ash.

The same batch of fish and HORECA waste will be used for all BBFs. Fermentation liquid does not need any additional ingredients and can already be used as a foliar spray. For the vermicompost, adding tree leaves is necessary to achieve an optimal 25-30:1 C-N ratio. For the granules, adding tree leaves to increase the content of C and ~10% wood-burning ash to balance the pH level is necessary. The challenge with the formulation lies in the fluctuation of the content of HORECA food waste stream. Hence, it will not be possible to provide exact nutritional or biostimulative data which would apply to all batches. The solution is to provide respective ranges. In general, the foliar spray has a high level of lactic acid bacteria, although its effect as a biostimulant requires further research; granule is an organic fertilizer with a potential as carbon storage in soils, and contains amino, fulvic and –humic acids; vermicompost is a potential growing medium that also requires further testing.

Figure 1: granules

 

Figure 2: vermicompost