(New throughout; updates prices, adds quotes, changes byline, changes dateline from previous PARIS/CANBERRA)

CHICAGO, Jan 30 (Reuters) -

U.S. corn and soybean futures rallied on Tuesday on a round of bargain buying after both commodities fell to multi-year lows, although supportive news about supply and demand was lacking, analysts noted.

Wheat followed the firm trend, bouncing after a slide to one-week lows.

As of 12:23 p.m. CST (1823 GMT), Chicago Board of Trade (CBOT) March corn was up 6-1/4 cents at $4.46-1/2 per bushel, rebounding after a dip to $4.36-1/2, the lowest on a continuous chart of the most-active contract since December 2020.

CBOT March soybeans were up 17-1/4 cents at $12.11-1/2 a bushel, bouncing after falling to $11.87-3/4, the lowest on a continuous chart since November 2021. CBOT March wheat was up 10-1/2 cents at $6.04 a bushel.

For the month, benchmark corn futures have fallen 5% and soybeans are down nearly 7%, reflecting increasing investor confidence about developing crops in Argentina and Brazil coupled with ample U.S. supplies after bumper 2023 harvests.

Commodity funds already hold sizable

net short positions

in all three grain markets, and traders appeared to be weighing whether prices would fall further, or if current fundamentals have been absorbed.

"A lot of us are still trying to decipher South American crop sizes," said Dan Basse, president of AgResource Company in Chicago. "Bear markets will end when we've digested all the news, and it's always a question if we have done that," Basse said.

Others expected that slow demand would continue to dog the grain markets, given a U.S. corn surplus and a lack of interest in U.S. soybeans from top global buyer China.

"Today is going to get a lot of people excited about the lows being in.... But we've got (an) over 2 billion bushel carry-over in corn. Without massive, massive sales, it's a long road to a tight balance sheet," said Ted Seifried, chief market strategist for the Zaner Group.

Condition

ratings

for winter wheat improved during January in Kansas, the top U.S. winter wheat producer, as drought eased in much of the Plains, although ratings declined in other states including Texas, the U.S. Department of Agriculture (USDA) said on Monday.

(Reporting by Julie Ingwersen; additional reporting by Gus Trompiz in Paris and Peter Hobson in Canberra Editing by Marguerita Choy)