Walters, however, told China Daily that farmers preferred market access over government bailouts.

"The farmers will welcome it and perhaps say 'this is not a long-run solution. We need market access. We need our market access back that we have built up over the years'," he said.

"They don't want to rely on government money," Walters said, adding that market access is paramount.

He suggested that even a small purchase from China could jolt the market and signal a willingness to buy. "Maybe that will shock the market so much that the futures prices would go up."

The USSEC's Salinas said a recent delegation to Beijing and Shanghai was warmly received by customers and stakeholders.

"We received a very good reception from the industry (and they said) that they would like to receive soybeans from the United States," Salinas said.

Christopher Wolf, a professor of agricultural economics at Cornell University, told the BBC, "China is just so big that when they buy things, it matters — and when they don't, it matters."

Salinas said he remained positive about the future of the US-China soybean trade relationship. He said China's Argentina deal for 5 million tons has limitations. "We understand China is looking for alternatives," he said.

Sutter was optimistic about the trade relationship. "Chinese buyers have always valued the consistent quality and reliability of US soybeans, which makes our product competitive when trade barriers are resolved," he said.

Belinda Robinson in New York contributed to this story.