By 2030, it is recommended to aim for a 50 percent share of renewable raw materials in professional growing media. This was published in a recent report by Wageningen University & Research (WUR), following independent research. In this research, RHP knowledge centre for substrates, provided technical expertise.
Following the signing of the Dutch covenant ‘Environmental impact of potting soil and growing media at the end of 2022, independent research by Wageningen University & Research (WUR) took place in 2023. In this research project, RHP knowledge centre for substrates provided a first technical consideration of potential new materials. In addition to what is already available in terms of raw materials, the focus was also on flows that are not yet in use and can only be made suitable after a certain processing.
Results
WUR summarizes the results of the independent research as follows:
- There are 5 groups of materials that are already available in significant quantities, which are coir products, wood fibre products, bark, composts and mineral products such as perlite.
- In addition, there are five groups of products with the potential to grow into products with the right volume, quality, price and security of supply. These are acrotelm, improved wood fibre, biochar, improved agricultural fibre, and semi-finished products.
- The recommendation for a content of renewable raw materials by 2030 is 50%. This is based on interviews with stakeholders and a division into sub-markets that can import renewable raw materials with varying degrees of ease.
- Managing risks for growers through adjustments in watering strategy, nutrient adjustments over time and adjustments in cultivation requires investments in knowledge, irrigation/nutrient equipment and measuring equipment.
- The risk of incidents involving human pathogens, plant pathogens, heavy metals, pesticides and drug residues, among other things, increases. Therefore, requirements for organisation and control will lead to a larger and sometimes strict certification system. Preventive plans will also have to be in place to limit and manage the impact of incidents.
- Low-hanging fruit consists of the further fractionation of materials, including mixing back into ideally balanced mixes.
- A great deal of emphasis will have to be placed on the development of processes that further stabilise wood and agricultural fibres. Additional research is urgently needed here.
- Research into sanitation processes around semi-finished products is also desirable, with attention to both the killing of diseases and pests and attention to the degradation of residues from, for example, pesticides.
- Competition is foreseen with the production of building boards for panelling and insulation, with energy products, with adhesive products, with stable litter, with bedding material and with soil improvement.
- By using legislation to promote the use of green flows and wood flows to composting companies, an additional 1-2 Mm3/year of compost can become available.
- The government can stimulate the production of raw materials such as acrotelm, willow, cattails, reeds, miscanthus, etc. by means of management agreements by giving marginal land or land set aside for nature value a function for the supply of biobased bulk raw materials.
Main conclusions
WUR mentions the following main conclusions in the report:
a. By 2030, it is recommended to aim for a 50% share of renewable raw materials (this ambition has been adopted in the Dutch covenant).
b. To expand the supply in the short term, existing raw materials coir, wood fibre, bark and compost can be further developed by:
- Further fractionation and fiberization.
- Merge fractions into predefined growing media with culture advice.
c. To expand the supply in the longer term, raw materials acrotelm, improved wood fibre, biochar, agricultural fibres and semi-finished products with compost can be further developed by:
- Stabilisation of wood and agricultural fibres.
- Increasing the area for paludiculture, semi-finished products and composts.
- Development of sanitation processes and, among other things, tests for semi-finished products.
d. Effectively supporting growers with training and information.
