Manure is a valuable resource for the biobased economy. A resource that should be used more efficiently, according to researchers from Wageningen UR Livestock Research. Together with the private sector, they are investigating innovative ways in which the Netherlands can become a frontrunner in giving manure the value it deserves. Karin Andeweg and Nico Verdoes explain why manure is an essential element of the circular economy.
Manure is rich in phosphate, nitrogen and potassium: all nutrients that are essential for plant growth. A worldwide shortage of phosphate is expected in the coming decades. In total, around two-thirds of the dry matter in manure consists of organic matter. Arable farmers, also in the Netherlands, have a particular need for it in order to maintain soil quality and soil fertility. It is therefore important to preserve organic matter within the agricultural nutrient cycle. Anaerobic digestion of organic substances in manure can also produce biogas, which can be used to generate electricity and heat.
The current Dutch policy on manure focuses primarily on reducing of environmental pressure on soil, water and air. A national phosphate ceiling has been defined for this purpose, causing a lot of phosphate and organic matter to be exported abroad. As well as being expensive, this prevents the optimal utilisation of manure, ignoring the fact that there are plenty of options to use manure as a valuable resource for the Dutch bioeconomy. To remedy this, we are together with the private sector investing in research in five areas:
To achieve optimal fertilisation and minimise losses in the nutrient cycles, we are working on making customised fertiliser products. This refers to products where the composition is tailored precisely to the needs of customers and the soil and crops they are growing.
We are investigating techniques to unlink phosphates and organic matter. This would allow us to use the phosphate from manure as resource for the ‘artificial’ fertiliser and animal feed industry, while the organic matter can be used by arable farmers.
Artificial fertiliser substitutes
To close the nutrient cycles, there is a need for fertiliser products that will substitute artificial fertiliser. Moreover, from a sustainability perspective, it is important to replace artificial fertiliser with products derived from animal manure. An example of a possible substitute for artificial fertilisers is mineral concentrate after reverse osmosis. Research by Wageningen UR into this product as a substitute for artificial fertiliser has shown that currently regulation is an obstacle for success.
Economic optimisation of biogas plants
Biodigestion on farm makes an important contribution to sustainability of the sector and supporting closed nutrient cycles. This technology is often economically unprofitable, however. Wageningen UR Livestock Research conducts a lot of research into making smaller plants profitable at farm level.
Quality raw materials
There are ample opportunities to refine manure into high-value bioactive substances. This is a novel and innovative approach. Wageningen UR Livestock Research is currently investigating the extraction of fibres from (cattle) manure to produce volatile fatty acids, amino acids, bioactive proteins, enzymes and peptides. It is important in this context that the concentrations of these substances in the manure are sufficiently high and of good quality, and that the production of the substances is economically viable. These are some of the great opportunities to use manure as a resource for the Biobased Economy.