GRAINS-Soybeans ease for 3rd session as U.S. harvest gathers pace

* Soybeans trade near 2-week low as U.S. harvests progresses in near-perfect weather

* Corn futures fall for 2nd consecutive session, wheat firms

* Investors square positions ahead of U.S. quarterly stocks report (Adds details on Ukraine’s wheat planting, fund positioning; updates prices)

SINGAPORE, Sept 30 (Reuters) - Chicago soybean futures slid for a third straight session on Wednesday, trading near their lowest in almost two weeks, as dry weather across much of the U.S. Midwest boosted harvest.

Corn slid for a second session, while wheat gained ground as traders squared positions ahead of widely watched U.S. report on grain and oilseed inventories.

The most-active soybean contract on the Chicago Board Of Trade (CBOT) slid 0.3% to $9.90 a bushel, as of 0302 GMT, having hit a Sept. 16 low of 9.85-3/4 a bushel on Tuesday.

Corn was down 0.3% at $3.63-1/2 a bushel, having closed down 0.6% in the previous session and wheat rose 0.4% to $5.51-1/2 a bushel.

The U.S. Department of Agriculture (USDA) late Monday said U.S. soybeans were 20% harvested, ahead of the five-year average of 15% and corn crop was 15% harvested, behind the five-year average of 16%.

The agency will report on Wednesday the amount of U.S. grains and soybeans stored on and off farms as of Sept. 1, a quarterly report that has a history of jolting CBOT futures markets.

The USDA on Wednesday will also update its estimates of U.S. 2020 wheat production.

It confirmed private sales of 100,000 tonnes of U.S. soybeans to Mexico, but the agency has not announced any fresh soybean sales to top global buyer China since Sept. 23.

Ukraine, hit by a severe drought, plans to cut its area under winter wheat to 6.1 million hectares from around 6.7 million a year earlier, its economy ministry said on Tuesday.

The ministry’s data showed farms had sown around 25% of the expected area as of Sept. 28 or 1.5 million hectares.

Commodity funds were net sellers of CBOT corn, soyoil, soybean, soymeal and wheat futures contracts on Tuesday, traders said. (Reporting by Naveen Thukral; editing by Uttaresh.V)