In this work package, we will explore the suitability of different waste resources as fertilisers in pot- and field experiments, and attempt to describe their quality by simple lab methods

Our studies include a wide range of materials, which are already available to farmers as waste-based fertilisers e.g. anaerobic digestate and compost based on food waste, sewage sludge, struvite based on wastewater, fish sludge, animal manure etc. (Figure 1)

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Figure 1. Some of the products used in the experiments. From top left to right: Dried fish sludge, biochar made from fish sludge, separated dairy manure. From bottom left to right: Dried liquid fraction of separated dairy manure, struvite made from waste water, separated swine manure. Photo: Eva Brod

We will study both the nitrogen and phosphorus quality of the waste resources during field and pot experiments (Figure 2 and 3).

For nitrogen , we will also test the ability of incubation experiments, chemical extraction methods and spectrometric methods to predict fertilisation effects of new fertiliser products.

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).

 

 

Click here for first results on nitrogen Click here for first results on phosphorus

Based on our results, we intent to propose prediction tools that can be used in fertilisation planning when waste resources are replacing mineral fertiliser products in agriculture.

Finally, we aim at developing guideline models for balanced nutrition application with waste-based fertiliser products. 

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Figure 3. Field experiment with biogas digestate. Photo: Annbjørg Ø. Kristoffersen
Contacts
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Figure 2. Pot experiment with different waste-based fertilisers rich in phosphorus. Photo: Kirsti Anker-Nilssen