GRAINS-Corn, soybeans slip on sound U.S. crop conditions, wheat slide continues

* U.S. surprises with improved soybean crop rating, steady corn condition

* Wheat loses more ground on harvest pressure (Adds details on U.S. crop condition, quote)

SINGAPORE, July 21 (Reuters) - Chicago corn and soybean futures slid on Tuesday after a better-than-expected U.S. Department of Agriculture (USDA) report on the condition of both crops.

Wheat fell for a fourth consecutive session as harvest across the U.S. Great Plains continued to weigh on the market.

The most-active corn contract on the Chicago Board Of Trade (CBOT) fell 0.6% to $3.33-3/4 a bushel by 0208 GMT, having closed 1.2% lower in the previous session.

Soybeans were down 0.4% at $8.96-3/4 a bushel and wheat lost 0.3% to $5.20-1/2 a bushel.

The USDA raised its good-to-excellent rating for the nation’s soybean crop on Monday and kept its corn rating unchanged, surprising analysts who expected a decline in the condition of both crops from a week ago.

The agency said in a weekly report 69% of soybeans were in good-to-excellent condition, up one percentage point from a week earlier, while analysts surveyed by Reuters expected a drop to 67%. Their good-to-excellent estimates ranged from 66% to 70%.

The good-to-excellent rating for corn was also 69%, unchanged from a week earlier. Analysts on average expected 68%.

Last week’s favourable weather led several U.S. Crop Watch growers to increase corn condition and yield scores, bringing those eight-field averages to the highest levels for any week since Crop Watch began in 2018, Karen Braun, a columnist for Reuters, wrote on Monday.

The soybean scores are also among the highest, but much of the corn could get by with one or two more good rains, while soybeans will still depend on good moisture through next month, she added.

“The U.S. (wheat) market looks to be searching for export sales,” said Tobin Gorey, director of agricultural strategy, Commonwealth Bank of Australia.

The wheat market is facing headwinds as bumper harvests across the Northern Hemisphere boost world supplies.

Commodity funds were net buyers of CBOT soybean, soymeal and soyoil futures contracts on Monday and net sellers of corn and wheat futures, traders said. (Reporting by Naveen Thukral; Editing by Vinay Dwivedi)