Chinese tariffs on a slew of American farm products have officially come into effect, the latest retaliation in the unfolding trade war between the world’s top two economies.

China’s willingness to use food as a countermeasure against the U.S., historically one of its biggest providers, underscores both the government’s success in boosting agricultural self-sufficiency and the impact of a slowing economy on demand.

The agricultural tariffs, which run from 10% to 15% on an expansive list of items including grains, proteins, cotton, and fresh produce, follow initial action focused on energy and critical metals. Soybean imports from three U.S. firms, as well as all American timber purchases, have also been halted.