U.S. soybeans slid to a one-month low on Monday as rains across Argentina eased fears over dry weather curbing yields while wheat also fell as uncertainty about demand from top buyer Egypt kept prices under pressure.

March soybeans on the Chicago Board of Trade was off 0.35 percent at $8.64-1/2 a bushel at 1217 GMT after dipping to a one-month low for the front month of $8.64-1/4.

"Argentina's summer crops did see some rainfall on Saturday - a good sign," said Tobin Gorey, director, agricultural strategy, Commonwealth Bank of Australia.

Drought has already caused irrecoverable corn crop losses in some areas of Argentina despite the El Nino weather event which usually triggers heavy rains in South America.

Wheat futures were lower weighed by uncertainty about trade with Egypt following the recent cancellation of two import tenders and the rejection of French cargo linked to the level of ergot fungus it contained.

March wheat in Paris was off 2.00 euros or 1.3 percent at 154.25 euros after dipping to a contract low of 154.00 euros which was also the weakest level for the front month since September 2015.

Egypt sought to reassure wheat markets on Sunday after weeks of confusion over the allowed limits of ergot fungus rattled traders.

"The Franco-Egyptian wheat saga seems to have the market somewhat concerned. Egypt's on again, off again, and most recently on again, rejection of a cargo of French wheat is worrying the market," Gorey said.

Russian wheat export prices have also fallen, undermined by worries about futures supply contracts to Egypt.

March CBOT wheat was down 0.3 percent at $4.65-1/4 a bushel.

CBOT corn prices were also weighed by favorable crop weather in South America with March down 0.3 percent at $3.64-1/2 a bushel.

Meanwhile, the market was turning its attention to the next U.S. Department of Agriculture supply and demand forecast due on Feb. 9. Analysts polled by Reuters expected USDA in its monthly supply outlook to show larger U.S. grain supplies but slightly lower world stocks.