For customs classification purposes, ammonium sulfate fertilizer is classified by its chemical identity and intended use, not by the production process. However, the byproduct origin can affect cost structures and pricing, which in turn influences antidumping margin calculations if a duty order is in effect. Importers sourcing from integrated chemical or steel producers should retain documentation of production origin to support any scope exclusion requests.

Ammonium sulfate is preferred on alkaline or high-pH soils where volatilization of urea-derived ammonia is a concern, and in crops with high sulfur demand such as canola, onions, and legumes. Its acidifying effect on soil pH is also valued in regions with naturally alkaline soils, making it a targeted rather than general-purpose nitrogen source.