Investors are diving into the commodity, sending bets on a rally to the highest since June 2014. The excitement comes amid signs of shrinking production in South America and forecasts for a La Nina pattern this year, which further threatens supplies with unfavorable U.S. weather.

Adding to the positive outlook are signs of increasing demand in China, the world’s top importer. China’s imports jumped 36 percent in March from a year earlier to 6.1 million metric tons, the highest ever for the month. American farmers are benefiting from the resurgence in demand as declines for the dollar against Brazil’s currency make their supplies more competitively priced. Sales of U.S. soybeans exceeded the prior five-year average for five straight weeks.

Soybean futures jumped 5.2 percent last week, the most since October. The optimism for prices marks a decisive shift from just five weeks ago, when money managers were net-short on the oilseed, or wagering on declines. With volatility still less than half of 2012 peak, the recent price rally is vulnerable to a “huge correction,” Roose said. Still, that’s unlikely to happen “until the supply risks subside,” he said by telephone April 15.

“As soon as fundamentals gradually started to change, funds started to get out of shorts and got long soybeans because they have the potential to move the most,” said Don Roose, the president of U.S. Commodities Inc. in West Des Moines, Iowa.