Abstract: A granular slow-release nitrogenous fertilizer which is less in the release velocity of a nitrogen component than a conventional granular slow-release nitrogenous fertilizer and which is excellent in long-term persistence and the sustained releasability of the nitrogen component. The granular slow-release nitrogenous fertilizer is prepared by granulating a mixture of a urea-aldehyde condensate and an oxidized wax. The content of the oxidized wax is preferably three to 25 weight percent and more preferably five to 15 weight percent. The oxidized wax contains polar groups and therefore has extremely excellent compatibility with the urea-aldehyde condensate. Therefore, the urea-aldehyde condensate, which is sparingly soluble, is extremely uniformly dispersed in the granular slow-release nitrogenous fertilizer according to the present invention; hence, the release velocity of the urea-aldehyde condensate into soil is low.

Abstract: A process for producing a granular slow-acting nitrogenous fertilizer, which comprises blending an aqueous methylol urea solution to a urea-isobutyraldehyde condensate powder or a mixture thereof with a urea-formaldehyde condensate powder, and granulating the resulting blend while subjecting the methylol urea to dehydration condensation under an acidic condition to form a urea-formaldehyde condensate.