* Soybeans sink on U.S. harvest data; corn weaker

* Wheat futures continue climb on bargain-buying

Oct 3 (Reuters) -

Chicago soybean futures fell on Tuesday to nearly their lowest levels since December of 2021, on improving signs for the U.S. harvest and as a brisk start to planting in Brazil created supply pressure.

Corn prices dropped on robust harvest data, while wheat edged up as it continued to recover from Friday's plunge to a three-year low after bargain buying from China.

Chicago Board of Trade (CBOT) soybeans were down almost 1.5% at $12.58-1/4 a bushel by 10:20 a.m. CDT (1520 GMT). The contract earlier reached its weakest since June 28 at $12.56-3/4.

The drop in soybeans followed the release of U.S. government data on Monday

rating

52% of the crop "good" or "excellent," beating analysts' expectations for 50%. The U.S. Department of Agriculture's (USDA) figures showed corn crop ratings were unchanged at 53% rated "good" or "excellent."

CBOT corn slid just over 0.8% to $4.84-3/4 a bushel.

Brokerage StoneX raised its estimates of U.S. 2023 corn and soybean production.

"As more producers get out there, they're seeing a little better than expected on the corn yield," said Darin Fessler, a senior vice president and market strategist with Lakefront Futures in Lincoln, Nebraska.

In Brazil, which competes with the United States in export markets, 2023/24 soybean planting reached 5.2% of the expected area last week, the quickest pace ever for the period, an agribusiness consultancy said.

CBOT wheat futures added 0.5% to $5.69-1/2 a bushel, extending gains from Monday on bargain-buying after prices fell more than 6% to a three-year low on Friday.

"The Chicago (wheat) market is dirt-cheap right now," said Fessler, responding to a USDA report on Tuesday on the sale of 220,000 metric tons of U.S. soft red winter

wheat to China

.

It was the first time China had purchased that particularly class of wheat from the U.S. since July 2021. (Reporting by Zachary Goelman in New York City; additional reporting by Gus Trompiz in Paris and Peter Hobson in Canberra; Editing by Paul Simao)