* Harvest of near-record soybean crop starts in Brazil

* Wheat slides as buyers search for cheaper options

* Corn futures down for second consecutive session

CHICAGO, Dec 30 (Reuters) - Chicago soybean futures fell sharply on Thursday, as the harvest of a near-record crop started in top grain exporter Brazil and more rain fell in dry stretches of Parana than expected, traders said.

Corn futures dropped for a second session on some profit-taking, even with news of better-than-expected export demand. Wheat futures fell as investors focused on Argentina and Australia's larger-than-expected crop, and higher prices keep U.S. wheat less attractive on the global market, traders said.

The Chicago Board of Trade (CBOT) most-active soybean contract settled down 30-1/4 cents to $13.38-1/2 a bushel.

Corn settled down 9-1/2 cents at $5.96 per bushel while wheat fell 8 cents to $7.79-3/4 a bushel.

Rain showers continued in northern Brazil, and reached more of central and southwestern Parana than previous weather models had predicted, Commodity Weather Group said on Thursday.

"Fear and greed drive the markets, and right now for soybeans, it's about fear," said Don Roose, president of Iowa-based U.S. Commodities. "The trade is thinking, 'uh oh, even when it's dry, we've seen you get a pretty good-sized crop.'"

The early Brazilian harvest also means China could soon start buying South American soybeans, at a time when the export market is typically dominated by U.S. offerings.

And Argentina could harvest more than the currently forecast 21.5 million tonnes of 2021/22 wheat if yields continue to come in higher than expected, the Buenos Aires Grains Exchange said in a report on Thursday, with 89.7% of the crop harvested so far.

Meanwhile, the U.S. Agriculture Department said on Thursday that export sales of wheat totalled 199,500 tonnes in the week ended Dec. 23, below the low end of analysts' forecasts that ranged from 200,000 to 500,000 tonnes.

Export sales of U.S. corn totalled 1.307 million tonnes, USDA said, above analyst forecasts.

Soybean export sales totalled 599,100 tonnes, missing trade estimates for 700,000 to 1.24 million tonnes. (Reporting by Naveen Thukral in Singapore and Sybille de La Hamaide in Paris; editing by Subhranshu Sahu, Jason Neely, Ramakrishnan M. and Diane Craft)