A dosage form with a sustained release rate for water-soluble and/or water-insoluble substances, such as fertilizers and/or nutrients and/or protecting agents for plants, animals and microorganisms in aquacultures, characterized in that said substances are incorporated individually or in the form of mixtures with one another in a finely divided form in a support insoluble in water, from which they are released in defined amounts over time at a highly reduced rate, the support being an elastomer cross-linked by high energy radiation.
