Fertilisers
There are all kinds of fertilisers: natural fertilisers, such as animal and green manure and, of course, a wide range of artificial fertilisers.
There are national and European policies regarding fertilisers and their application. The Mineral Reporting System (Minas) and Decree on the quality and use of other organic fertilisers observe strict guidelines on quantities, etc.
The composition of and heavy metals in, natural fertilisers and the purity of, and impurities in, artificial fertiliser can only be measured with advanced laboratory equipment and standardised methods.
Materials such as compost (including mushroom compost), etc. are subject to strict monitoring by suppliers and users, too.