GRAINS-Soybeans extend gains after USDA's US harvest outlook cut

By Karl Plume

CHICAGO, Aug 13 (Reuters) - U.S. soybean futures climbed to a 1-1/2 month high on Wednesday, extending gains from the prior session after the U.S. Department of Agriculture forecast a much smaller autumn harvest than previously expected.

Corn also edged higher in a modest technical and short-covering rebound from Tuesday's more than 3% drop to contract lows after the USDA's larger-than-anticipated corn crop outlook.

Chicago Board of Trade wheat was slightly higher after setting another five-year low earlier in the session, although hefty global supplies continued to hang over the market.

The USDA said on Tuesday U.S. farmers would produce a record-breaking corn crop in 2025/26, as the agency surprised traders with steep upward revisions to both yield and area projections. The record U.S. harvest is set to further bolster global supply as Brazil wraps up a bumper harvest while in Ukraine, another major exporter, crop expectations are rising.

Meanwhile, the USDA's U.S. soy harvest outlook was much smaller than expected following a steep cut to planted acres.

"When you drop the soybean acres by that much, 2-1/2 million harvested acres, and when you don't change the demand a whole lot, that market is going to react," said Don Roose, president of U.S. Commodities.

CBOT November soybeans SX25 settled 11-1/2 cents higher at $10.44-1/4 a bushel. The actively traded contract, after breaking through technical resistance at key moving averages on Tuesday, filled a chart gap around $10.44 and reached its highest since July 3.

December corn CZ25 was up 2-3/4 cents at $3.97-1/4 a bushel and CBOT September wheat WU25 rose 2-1/4 cents to $5.07-1/4 a bushel.

Harvest progress in the Northern Hemisphere continued to weigh on wheat. The market was also awaiting Friday's meeting between U.S. President Donald Trump and Russian counterpart Vladimir Putin as a Russia-Ukraine ceasefire could facilitate exports from the major wheat-producing countries.