A collaborative study by SYSTEMIC researchers from Ghent University and Wageningen University Research was recently published in the Journal of Soils and Sediments. The title of their paper is titled “Solid fraction of separated digestate as soil improver: implications for soil fertility and carbon sequestration”.
The article compares the stabilities of organic carbon and nitrogen present in different solid fraction of digestates that were produced in two SYSTEMIC demonstration plants. The results showed that although the nutrient composition of solid fraction of digestates are variable, they generally follow a similar carbon mineralization pattern. Compost and biochar are more stable meaning that a larger fraction of the organic remains in soil as compared to solid fractions from manure. In terms of nitrogen, some solid fractions may cause temporary nitrogen immobilization. They also found that reducing the phosphorus content (via Re-P-eat) offers the best alternative for the use of solid fractions as soil improvers, especially in regions with limits on phosphorus input.
Reference and link towards the article: (open-access)
Egene, C.E., Sigurnjak, I., Regelink, I.C., Schoumans, O.F., Adani, F., Michels, E., Sleutel, S., Tack, F.M.G., Meers, E., 2020. Solid fraction of separated digestate as soil improver: implications for soil fertility and carbon sequestration. J Soils Sediments. DOI: 10.1007/s11368-020-02792-z