In the scope of reducing the use of limited natural resources, such as phosphorus, which is mainly a mined resource, recycling-derived fertilisers (RDFs) seem to be a good alternative to synthetic fertilisers.
Thanks to the multi-actor dynamic characteristic of European projects, ReNu2Farm is developing at a fast pace tomorrow’s circular economy of RDFs in North-West Europe. After involving farmers and SMEs to understand their expectations on demand, supply, form, nutrient content of RDFs, a mapping of nutrient demand has been created to better visualise the needs of each region. As a result, the product would be more attractive for farmers if the fertiliser composition gets adapted to regional and crop-specific needs.
At the same time, one strand of the project focuses on comparing the availability of nutrients like phosphorus in the soil for several RDFs. The phosphorus of the organic RDFs can be of mineral or organic forms. In most cases the mineral form is predominant. The chemical form depends on the origin of the product (animal species and way of feeding them…), as well as possible treatments applied (composting, liming, heat treatments…). The origin and the treatments before spreading can influence the short-term availability of phosphorus. On the field, RDFs provided by several suppliers are tested in France by Arvalis to assess the short, mid and long term availability of phosphorus in the soil, a challenge for fertilisation planning. Different types of fertilisers are tested, such as ashes, struvite and three sorts of compost from pig and poultry manure. Then soil samples were taken and sent to partners for microbiome and nematode analysis. Product samples were also sent to compare different methods to determinate short-term P availability and identify the most effective one (lab vs field experiments).
