PURPOSE: The elution sustaining time of the fertilizer is less changed even in diversified cultivation methods and decomposition progresses rapidly in a natural environment after elution of the fertilizer components. This decomposable film has a lag time in the initial period of decay and decomposition and, therefore, the supply of more than the needed fertilizer components in the initial period of the cultivation of crops can be prevented and the adverse influence, such as concn. fault on the crops, is prevented.

CONSTITUTION: This coated granular fertilizer is coated with the decomposable film contg. a vinyl resin and is constituted by incorporating at least one kind of the following metal complexes into this vinyl resin: 1) The 1st complex : A complex forming agent is bonded to a metal via oxygen and the metal is a transition metal. 2) The 2nd complex: A complex forming agent is bonded to a metal via sulfur and the metal is a transition metal or the metal belonging to group II or IV of element periodic table.