CHICAGO: Chicago soyabean futures reached four-year highs on Thursday as dryness in South American crop areas raised supply concerns at a time of brisk Chinese demand. Corn and wheat hit one-week highs on strong demand and supply concerns.

The most-active soyabean contract on the Chicago Board of Trade was up 16-1/2 cents at $11.02-3/4 a bushel at 11:15 a.m. CST (1715 GMT), after climbing to $11.12-3/4, its highest since July 14, 2016.

Corn added 5-1/2 cents to $4.10-1/2 a bushel and wheat rose 4-1/4 cents to $6.10-1/4 a bushel.

Dry weather affecting corn and soyabean planting in South America, as well as winter wheat seeding in the United States and Russia, threatens to trim ample global supplies as China drives global demand.

"If things don't improve weather-wise in South America," said Dan Hussey, senior market strategist at Zaner Group, "We really are in a situation of one of the tightest carryouts we've seen in a long time."

Weekly US export sales data showed net sales of 2.6 million tonnes of corn for the 2020/2021 marketing year, up 16% from the previous week and 75% from the prior 4-week average, while soyabean sales dropped to 1.5 million tonnes, down 6% from last week and 32% from the prior 4-week average, according to the US Department of Agriculture.

A weaker dollar and firmer share prices also lent support to grain markets as investors saw a possible conclusion to a tight US election, with Joe Biden edging towards victory over President Donald Trump in result projections. An unchanged Congressional makeup eased worries of drastic Democratic policy shake ups.

"They (farmers) were really concerned about losing the Senate, doing the Green Deal and all these taxes," said Mike Seery, president of Seery Futures. "Get rid of that, there's a big relief rally."