News Sunday that China launched investigations that could block imports of U.S. grain sorghum sent shock waves through a market already on edge as trade tensions between the two economic powers rise.

The probe alleges Chinese farmers are harmed by U.S. dumping and subsidies for the feed grain, which previously escaped China’s efforts to limit imports. It comes just days after President Trump announced tariffs on imports of solar panels and washing machines  -- China has a huge solar industry.

Here’s what the dispute is about – and why it’s crucial for U.S. farmers.