Chicago soybean futures rose again on Monday, hitting their highest since August, as an estimate from the U.S. Department of Agriculture (USDA) of reduced U.S. plantings in 2016 continued to support prices.

Wheat rose to its highest in around three weeks, while corn dropped for a third session out of four.

"The markets today seem to be still showing spillover impact of the USDA report last week, with the estimate of expanded corn sown area in the United States weakening corn and expected reduced U.S. sowing underpinning soybeans and wheat," said Matt Ammermann, commodity risk manager- vice president eastern Europe/Black Sea region for INTL FCStone.

Chicago Board of Trade most-active May soybeans rose 0.3 percent to $9.21 a bushel at 1020 GMT, near their session peak of $9.22-1/4 a bushel, the highest since Aug. 17. Most active May corn fell 0.4 percent to $3.52-1/2 a bushel and most active May wheat was up 0.05 percent at $4.76 a bushel.

On Thursday, the USDA said U.S. farmers planned to sow 82.236 million acres of soybeans this year, the third-highest area ever but below 82.650 million a year ago and under an average trade forecast of 83.057 million. The USDA said farmers were planning to increase corn seedings by 6.4 percent to 93.601 million acres, the third-highest level since 1944.

"Fundamentals in corn remain bearish, the market is also awaiting more details about China's state purchasing changes," Ammermann said. "Soybean markets are firm but overall global supplies are expected to be large despite the likely reduction in U.S. acreage."

"There was some buying interest late on Friday which supported soybeans but this now largely quiet. The wheat market is close to last week's resistance in Chicago of $4.80."

The Commodity Futures Trading Commission's weekly commitments of traders report also showed that non-commercial traders, a category that includes hedge funds, trimmed their net short position in CBOT wheat and raised their net long position in soybeans.

"Friday's positions report indicated that investors had added to their long beans positions. And, chances are, they have probably continued to do so given the lower-than-expected U.S. planting estimates," said Tobin Gorey, director of agricultural strategy at Commonwealth Bank of Australia.

In wheat, dry weather in the U.S. Plains again caused concern about possible stress to the hard red winter wheat crop.

Wheat seedings for 2016 were forecast by the USDA at a smaller-than-expected 49.559 million acres.