In work package 2, we will explore the suitability of a wide range of waste resources as fertilisers in pot- and field experiments. We will also study chemical characteristics of the waste resources by in-depth laboratory studies. Our studies include anaerobic digestate and compost based on food waste, sewage sludge, struvite based on wastewater, fish sludge, animal manure, wood ash etc. We will study both the nitrogen and phosphorus quality of the waste resources.

Further, we aim at identifying a set of analytical parameters to predict the nitrogen and phosphorus fertilisation effects compared with mineral fertilisers. We intent to propose prediction tools that can be used in fertilisation planning when waste resources are replacing mineral fertiliser products in agriculture. For nitrogen, we will test the ability of incubation experiments, chemical extraction methods and spectrometric methods to predict fertilisation effects. For phosphorus, we aim at verifying previous suggestions to predict fertilisation effects by the fraction of phosphorus being soluble in 0.5 M NaHCO3 (Olsen P method).

Finally, we aim at developing guideline models for balanced nutrition application, when waste resources are used as fertiliser in agriculture.

Photo: Annbjørg Ø. Kristoffersen