|Agricultural products from the US land raw materials like steel from China are pretty fungible.|
The immense firms Cargill and Louis Dreyfus buy and process soybeans in both America and Brazil, so it's inevitable American soybeans continue to flow to China.
The diversion just means more costs, and thus lower prices for US farmers.
The largest American pork grower and processor, Smithfield Foods, based in Smithfield, Virginia was bought by WH Group of China in 2013 for $5 billion and has huge operations in Mexico as well.
If Smithfield can't sell US pork in China due to tariffs, they will be selling them the pork from their Mexican farms, along with Mexico's largest pork producer, Granjas Carroll. - reuters.com
Trump eliminated steel and aluminum tariffs on Canada provided they institute tracing to avoid these metals from China from being sold in the US as Canadian, but like soybeans and pork, it won't be possible to completeley eliminate this.