GRAINS-Chicago soybeans, corn slip ahead of USDA report; wheat gains

BEIJING, Jan 12 (Reuters) - Chicago soybean futures slipped on Monday as traders positioned ahead of the closely watched U.S. Department of Agriculture (USDA) crop report, while competition from top producer Brazil weighed on prices amid a gradually advancing harvest.

The most-active soybean contract on the Chicago Board of Trade (CBOT) Sv1 fell 0.05% to $10.62 a bushel as of 0412 GMT.

China has been steadily buying U.S. soybeans following a trade truce in late October.

On Friday, Sinograin purchased at least 10 cargoes of U.S. soybeans, moving closer to fulfilling a commitment to buy 12 million metric tons of the latest U.S. soybean harvest by the end of February.

On Tuesday, Sinograin will auction 1.1 million tons of imported soybeans as the state stockpiler works to make room for arriving U.S. shipments.

In Brazil, harvest activity is gradually picking up. Consultancy firm Patria AgroNegocios said on Friday that farmers have harvested 0.53% of the country's expected 2025/2026 soybean area, compared to 0.05% at this time last year.

CBOT wheat Wv1 climbed 0.58% to $5.20-1/4 a bushel. Corn Cv1 lost 0.06% to $4.45-1/2 a bushel.

Traders are closely watching Monday's USDA grain report, which will include winter wheat planting estimates, last year's corn and soybean harvests, and U.S. grain stock levels as of December 1.

Analysts expect the USDA to lower its projections for U.S. soybean export demand in the current crop year due to weaker sales to China.

Estimates for the U.S. corn and soybean harvest are also expected to be trimmed, partly reflecting dry autumn weather.

Wheat had been supported by dryness concerns in the U.S. Plains, though some traders said it was too early in the season for dry conditions to materially affect winter wheat yields, with crop conditions still looking relatively good across the region.