GENEVA (Reuters) -U.S. soybean exports may drop 20% and the prices paid to farmers will plunge if the United States and China fail to reach a deal in their trade dispute limiting U.S. soybeans from its largest market, agribusiness consultants AgResource said on Wednesday.

U.S. soybeans exports could slump to 1.5 billion bushels from an initial estimate of 1.865 billion without a deal, AgResource President Dan Basse told Reuters on the sidelines of the GrainCom conference in Geneva.

At the same time, U.S. soybeans farm gate prices - the average price paid to farmers - may collapse to $9.10 bushel in 2025/26, compared to $10.25 a bushel forecast by the U.S. Department of Agriculture, Basse said.

"It's important that any U.S./China trade deal happen by late summer or the export forecast will become reality pressuring U.S. farm income. The clock is ticking," he said.

The temporary truce in the U.S.-China trade war, announced on Monday, would not help U.S. farmers revive soy sales in China as Chinese duties, even reduced to 10% from 145%, remained too high to make U.S. soybeans competitive.

"The truce helps but Brazil will have an additional 20 million metric tons of soybeans to export on September 1," Basse said.

China has been a critical market for U.S. farmers representing more than half of U.S. soybean exports in the most recent marketing year.

However, American farmers worry the tariff pause will not be enough to help them, as Brazil, the biggest soy supplier to China, has ample supplies from a record harvest, lower prices, and its farmers do not face any Chinese tariffs. 

China, the world's largest crop importer, already sources roughly 70% of its soybean imports from Brazil.