The distinction often turns on whether the product's primary function is a direct pesticidal or fertilizing action versus a mechanical, structural, or adjuvant role. CBP's classification principles look to the product's essential character and principal use. When a product straddles both functions, a binding ruling request is the most reliable way to confirm the correct HTS heading before importation.

Yes — many agricultural inputs, including certain equipment components and chemical precursors, are subject to Section 301 tariffs when originating from China. The applicable list and rate depend on the specific HTS subheading. Importers should review the current Section 301 annexes and consult a licensed customs broker to assess exposure before placing orders.