At the Kimberley family farm in rural Iowa the winter frost has lifted and the next few weeks will bring soybean planting season.
"One in every three rows of beans goes to China," said Grant Kimberley, watching a combine harvester spraying fertilizer across a vast field.
But Mr Kimberley, 42, whose ancestors have tilled the soil here since the 1860s, didn't look overly confident those exports would continue.
A potentially devastating trade war looms and US soybeans headed for China could face a 25 per cent tariff. The proposed tariff hangs like a sword of Damocles over Iowa, a state bigger than England known as the "breadbasket of America".
Forty per cent of China's soybeans, $14 billion worth...