In which substrate raw materials do pesticide residues occur? And what are their possible consequences for cultivation? RHP, knowledge centre for substrates, investigates it.
Substrate raw materials often have a previous history from another chain. In that chain, pesticides (then permitted) may have been used in the past.
For several years, RHP has been investigating whether residues occur in substrates. By default, RHP scans raw materials for residues of 1056 substances. Because measuring techniques become better and better, very low concentrations can already be demonstrated. Meanwhile, RHP has gathered the necessary insights about residues in raw materials.
There is no residue in peat, but residues (low concentrations) have been found regularly in renewable or circular feedstocks. In compost most often. This is due to the green waste used. Residues have also been found in (composted) tree bark, wood fibre and coconut products, for example.
RHP has now started research into the extent to which plants absorb these residues. For that purpose a substrate is made with raw materials in which residue has been found. The plants which are grown on this, RHP investigates on possible present residues. The research into plant uptake is now in full swing.
Any residue uptake by the plant will partly depend on the type of pesticide and the concentrations (which are often low). RHP wants to know what any risks are to the plant and (in case of edible crops) to humans. At the end of this year, more will become clear about this.
RHP has released a fact sheet on the study of residues in substrates. This and other RHP fact sheets can be found at https://www.rhp.nl/en/factsheets
About RHP
RHP is the quality mark and knowledge centre for substrates. It has been doing independent, innovative research into the properties of renewable and circular raw materials for years. With this research knowledge, internationally affiliated companies create products at the very highest level. Besides quality and safety of substrates, sustainability gets more and more attention.