The present invention provides a granulated agricultural composition in which the stability of an organophosphorus compound as an active ingredient is improved. The present invention relates to a granulated agricultural composition comprising an organophosphorus compound and calcined clay, relates to a process for producing the above granulated agricultural composition comprising an organophosphorus compound as an active ingredient, which comprises compounding calcined clay to improve stability of the active ingredient, and relates to a method for improving stability of an active ingredient comprised in a granulated agricultural composition, comprising compounding calcined clay, wherein the active ingredient is an organophosphorus compound.
