Soybeans are the single largest American export to China in terms of value, $12.6 billion worth last year. But as the fall harvest gets underway across the country — 9 percent of planted beans had been harvested as of last week — the country that bought 52 percent of all American soybean exports last year is completely absent.

Sept. 1 was the beginning of the new marketing year for soybeans, the starting point for big sales. Instead, China hasn’t bought any American soybeans since May.

The cause is retaliatory tariffs China has placed on the United States, making the price of American soybeans unattractive for buyers there. Throughout the summer, farmers hoped the Trump administration and China would reach a trade agreement that would drop the tariff on their crops, but so far, no relief was forthcoming.