Spillover support from rising wheat futures also gave corn and soy a lift ahead of eagerly awaited US Department of Agriculture (USDA) crop supply and demand data due later this week.
Weather forecasts pointed to warm temperatures in the US Midwest farm belt along with some showers in the week ahead, which could further boost yield prospects for corn and soybean crops that have been recovering from rain-delayed spring planting.
The USDA is scheduled to update its US corn and soybean crop forecasts in a monthly report on Thursday. The agency was criticized for its August forecast, which many farmers and traders said did not fully reflect early-season crop stress.
"The trade is looking for a cut of three bushels an acre in corn yields and a small reduction in soybean yields. You're seeing some short-covering going into that report, anticipating USDA to make larger revisions than that," said Brian Hoops, president of brokerage Midwest Market Solutions.
Forecasts for beneficial crop weather across much of the US Midwest anchored prices.
"Increasing warmth through the end of September, as well as low frost/freeze risks continues for the core corn and soy production areas," Refinitiv Agriculture Research analysts said in a note.
"The latest satellite imagery points to overwhelmingly positive late-season conditions in most major agricultural areas."
Chicago Board of Trade December corn fell to a contract low of $3.52-1/4 a bushel and was trading 3/4 cent higher at $3.56-1/4 at 11:47 a.m. CDT (1647 GMT). November soybeans were up 3-1/4 cents at $8.61 a bushel after earlier sinking as low as $8.51 a bushel, the lowest since May 24.
Wheat futures rebounded from early lows on technical buying and short-covering, and on concerns about Southern Hemisphere wheat crops.
Dryness in western Argentina and eastern Australia has stoked worry about lower yields in the key export nations.
CBOT December wheat jumped 11-1/2 cents to $4.75-1/4 a bushel in the contract's strongest gain in two months. Buying accelerated as the actively traded contract breached chart resistance at its 10- and 20-day moving averages and a down-trend line that traced the market's nearly 20% drop since late June.?Reuters