The prepn. of longer-lasting mineral fertilisers (I) from readily soluble N, P and K fertilisers, comprises coating the granulated fertiliser with a mixt. of resin and hardeners of a two component resin system such as epoxide-, polyester- and polyurethane resins or using the mixt. of resin and hardeners as the granulatng auxilliary so that a film of resin tightly seals the readily water-soluble fertiliser salts and prolongs solubility, thus prolonging availability of (I). USE/ADVANTAGE - The readily water-soluble N, P and K fertiliser salts are treated in such a manner, using conventional technology, that there is delayed release of the fertiliser salts in the soil and rapid backing out of the nutrients is prevented. The supply of nutrients to the plants is ensured over several growth phases and pollution of the environment is largely avoided. The free-flowing quality of (I) remains excell
