This U.S. industry comprises establishments primarily engaged in mixing ingredients made elsewhere into fertilizers. Cross-References. Establishments primarily engaged in-- ? Manufacturing nitrogenous fertilizer materials or fertilizer materials from sewage or animal waste and mixing these ingredients into nitrogenous fertilizers--are classified in U.S. Industry 325311, Nitrogenous Fertilizer Manufacturing; and ? Manufacturing phosphatic fertilizer materials and mixing ingredients into fertilizers--are classified in U.S. Industry 325312, Phosphatic Fertilizer Manufacturing.