The invention relates to a process for preparing a reduced-release chemical fertilizer. According to the invention, the process consists in forming in situ a mixed divalent metal-ammonium phosphate and encapsulating this material by polycondensating in suspension-emulsion, in a single stage, technical-grade urea with a technical urea-formaldehyde precondensate, to result in a product as micro capsules agglomerated as granules comprising 17...20% total nitrogen, 26...30% phosphor expressed as phosphor pentoxide, 4...5% calcium and 2...3% magnesium, at a nutrient levigation percentage of 55...65% for nitrogen and phosphor and 15...21% for calcium and magnesium, determined at 28 days.
