The major wildcard in whether soybean stocks continue to shrink is the South American crop, which is being planted now. Should South America have favorable weather, Hurt said the crop could make up for the shortages from the U.S. yields. This is especially true since farmers in countries such as Argentina and Brazil will grow more acres of soybeans than in previous years.

"The amount of Chinese soybean purchases will be up 9 percent this year," he said. "South American exports will increase, as both Argentina and Brazil have about 5 percent more acres and should return to more normal yields after a 5 percent below-trendline yield last year. South America will cover all of the new purchases from China."

If the weather in South America holds up, farmers in the United States can expect to see soybean prices remain strong through Thanksgiving, Hurt said. After that, prices could be fairly flat through the winter. However, unfavorable growing conditions in South America would send prices up quickly.

USDA currently expects the U.S. average farm price for soybeans to range from $12.65 to $14.65 per bushel.

"Prices are expected to provide a positive return for on-farm storage into December or January, but maybe not beyond," Hurt said. "Commercial storage may not pay this year, especially if the South American crop is large."

Corn farmers also aren't likely to see a profit from commercial storage. USDA projects average farm prices for corn at a record high $6.50 to $7.50. Hurt said on-farm storage looks profitable into spring and early summer, with prices rising more than enough to cover storage costs.

The full USDA-NASS report is available for free download at http://usda.mannlib.cornell.edu/MannUsda/viewDocumentInfo.do?documentID=1046