* Wheat dips 0.4 pct after two days of short-covering gains * Corn, soybeans little changed ahead of USDA report (Adds details, quotes) By Naveen Thukral SINGAPORE, Oct 12 (Reuters) - Chicago wheat ticked lower on Wednesday after two days of gains as investors positioned themselves ahead of the U.S. government's monthly report on the supply and demand of agricultural products. Corn and soybeans were largely unchanged ahead of the U.S. Department of Agriculture report which is expected to show an increase in soybean yields and a cut in corn production estimates. Chicago Board of Trade most-active wheat contract fell 0.4 percent to $4.05-3/4 a bushel by 0240 GMT, after gaining 3.2 percent in the past two days. Corn was unchanged at $3.45-1/2 a bushel and soybeans flat at $9.54-1/4 a bushel. "It is mainly positioning before the USDA report," said Kaname Gokon at brokerage Okato Shoji in Tokyo. "Soybeans yields may be increased while corn production numbers are likely to be reduced. For wheat there are some concerns for wheat output in some areas but overall supplies are still pretty ample." After the market close on Tuesday, the USDA said the U.S. corn harvest was 35 percent complete by Sunday, behind the five-year average of 38 percent, and the soybean harvest was 44 percent complete, lagging the five-year average of 47 percent. The latest figures fell short of analyst expectations for corn harvest progress to reach 38 percent and soybeans to reach 48 percent. The USDA's October supply and demand report is due at 1600 GMT on Wednesday. Analysts surveyed by Reuters on average expected the USDA to lower its estimate of the U.S. 2016 corn yield from 174.4 bushels per acre in September to 173.5, which would still be an all-time high. Analysts expect the government to raise its U.S. soybean yield estimate to 51.5 bushels per acre, up from USDA's September figure of 50.6, also a record high. The agency said export inspections of U.S. soybeans in the latest week were at 1.8 million tonnes, above a range of trade expectations for 1.0 million to 1.2 million tonnes. In news, Australia is expected to harvest a near-record wheat crop in 2016/17, slightly ahead of official estimates, a Reuters poll shows, but recent heavy rains may lead to quality downgrades and curb exports. The world's fourth-largest wheat exporter is set to produce 28.35 million tonnes, a poll of 10 analysts and traders found, just ahead of Australia's most recent official estimate of 28.1 million tonnes made in September. Commodity funds were net buyers of CBOT corn, wheat and soybean futures on Tuesday. Grains prices at 0240 GMT Contract Last Change Pct chg Two-day chg MA 30 RSI CBOT wheat 405.75 -1.50 -0.37% +2.79% 400.98 60 CBOT corn 345.50 0.00 +0.00% +1.69% 335.03 65 CBOT soy 954.25 0.00 +0.00% -0.26% 959.46 45 CBOT rice 10.36 -$0.04 -0.34% +2.63% $9.78 80 WTI crude 50.92 $0.13 +0.26% -0.84% $46.50 69 Currencies Euro/dlr $1.105 -$0.015 -1.35% -0.91% USD/AUD 0.7586 0.001 +0.15% +0.05% Most active contracts Wheat, corn and soy US cents/bushel. Rice: USD per hundredweight RSI 14, exponential (Reporting by Naveen Thukral; Editing by Christian Schmollinger)