* Soybeans underpinned by strong demand for soyoil, exports
* Firm Black Sea wheat prices support Chicago futures
(Adds details, quotes) SINGAPORE, Sept 5 (Reuters) - Chicago soybeans rose for a third consecutive session on Tuesday with prices climbing to a the highest in almost a month as expectations of strong demand underpinned the market. Wheat gained more ground as firm prices in the Black Sea region, a rival exporter to the United States, boosted U.S. export prospects. The Chicago Board of Trade most-active soybean contract rose 0.6 percent to $9.55 a bushel by 0256 GMT. That was near the session-high of $9.56-3/4 a bushel, the strongest since Aug. 10. Wheat gained 0.5 percent to $4.40-3/4 a bushel, after ending up almost 1 percent on Friday and corn added 0.4 percent to $3.56-1/2 a bushel, having closed down 0.7 percent in the previous session. U.S. markets were closed on Monday for the Labor Day public holiday. Soybeans were supported by a fall in U.S. soyoil supplies and expectations for stronger export demand. In addition, there are expectations of increased demand from the soy-based biodiesel sector after the U.S. government in August slapped tariffs on imports of Argentine biodiesel.
"Now that U.S. soybean crop has nearly been made, the market is going to be focused on demand side," said one India-based agricultural commodities analyst. "Bearish news has been priced in and it looks positive on the demand front." In the wheat market, Russian export prices fell for a fifth consecutive week, under pressure from a large new crop, but their decline was limited by a strengthening rouble against the dollar, analysts said on Monday. Black Sea prices for Russian wheat with 12.5 percent protein content and September delivery were at $179.50 a tonne on a free-on-board basis at the end of last week, down 50 cents from the week earlier, IKAR agriculture consultancy said in a note.
"Black Sea wheat prices are holding up well because of strong currencies and this has made U.S. wheat more competitive," IKAR said. Corn prices came come under pressure on Friday as confidence grows that U.S. output will be larger than previously expected. Private analytics firm Informa Economics on Friday raised its estimate of the U.S. 2017 corn yield to 169.2 bushels per acre (bpa), up from 165.9 bpa a month ago, three trade sources said. Informa also increased its U.S. 2017 soybean yield estimate to 49.4 bpa, from 47.3 bpa last month. The firm estimated soybean production at 4.384 billion bushels and corn production at 14.123 billion bushels.
Grains prices at 0256 GMT
Contract Last Change Pct chg Two-day chg MA 30 RSI CBOT wheat 440.75 2.00 +0.46% +1.44% 462.39 64 CBOT corn 356.50 1.25 +0.35% -0.35% 369.67 45 CBOT soy 955.00 5.50 +0.58% +1.03% 957.05 61 CBOT rice 12.90 -$0.04 -0.35% +0.58% $12.62 75 WTI crude 47.42 $0.13 +0.27% +0.40% $48.19 51
Euro/dlr $1.191 $0.001 +0.09% +0.41% USD/AUD 0.7967 0.003 +0.31% +0.00%
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)