GRAINS-Soybeans, corn rise thanks to sliding dollar, hot Argentina weather

Jan 28 (Reuters) - Corn and soybean futures on the Chicago Board of Trade climbed on Wednesday as the market grappled with hot and dry conditions in Argentina that could damage crops and a weakening U.S. dollar.

Wheat futures also rose.

The most-active soybean CBOT contract Sv1 had gained 0.7% to $10.74-1/2 a bushel by 0539 GMT. CBOT corn Cv1 was up 0.5% at $4.28-1/2 a bushel and wheat Wv1 rose 0.9% to $5.27-3/4 a bushel.

The U.S. dollar sat near a four-year low reached on Tuesday. The greenback has slipped around 3% against a basket of major currencies since January 20 as investors worried about U.S. President Donald Trump's pursuit of Greenland and domestic policies. USD/MKTS/GLOB FRX/

A weaker dollar makes U.S. commodities cheaper for buyers with other currencies, which can boost demand.

"That lower U.S. dollar is certainly doing good things from an export perspective for U.S. prices," said Sean Hickey, an analyst at Bendigo Bank Agribusiness.

In South America, meanwhile, intense hot and dry weather have hit Argentina, threatening crop production in the world's leading exporter of soy meal and soy oil and third-largest supplier of corn.

Argentina's key agricultural regions are in urgent need of rain after temperatures rose to near 104°F (40°C) in recent days, but significant relief is not forecast until February.

With planting nearly finished, the dry spell is hitting as 93.1% of corn and 96.2% of soybean acreage has already been sown, the Buenos Aires Grains Exchange said.

Traders are also closely monitoring cold weather in U.S. and Russian wheat-growing regions, Hickey said. "There's a little bit of concern about how that snow cover is going to protect against any Arctic blasts."

However, plentiful global supply of soybeans, corn and wheat is keeping a lid on prices, which remain far below their peaks in 2022.

Agricultural consultancy Sovecon on Tuesday raised its 2025/26 Russian wheat export forecast by 1.1 million metric tons to 45.7 million tons. Russia is the biggest wheat exporter.