[57] An anti-caking method for an agricultural chemical active ingredient in a composition comprising the agricultural chemical active ingredient and an inorganic substance, characterized by adding the inorganic substance to a powder of the agricultural chemical active ingredient which is solid at room temperature, wherein the inorganic substance is added in an amount of from 1 to 10 wt% to the agricultural chemical active ingredient; the inorganic substance is a powdery or granular bentonite or white carbon; and the powder of the agricultural chemical active ingredient is a powder having an average particle size of from 1 to 300 mm of a fungicidally active ingredient 3-chloro-N- (3-chloro-5-trifluoromethyl-2-pyridyl) –α, α, α-trifluoro-2,6-dinitro-p-toluidine.
