* US corn stocks below market forecast, plantings seen smallest since 2010
* Soybean stocks lower vs year-ago, but record large planting seen (Updates prices)
By Manolo Serapio Jr
April 1 (Reuters) - U.S. corn futures hit seven-month highs on Tuesday after a government report showed corn stockpiles in the world's top exporter were below market estimates and forecast farmers will plant the smallest amount since 2010.
Tighter U.S. supplies also helped lift old-crop soybean futures to a fresh contract high although new-crop prices were pressured by projections for a record large U.S. planting program this year.
Corn contract for May delivery on the Chicago Board of Trade hit a session peak of $5.05 a bushel, the highest since Sept. 3. It was up 0.1 percent at $5.02-1/2 by 0705 GMT, adding to Monday's 2 percent gain.
U.S. corn stockpiles were 7.006 billion bushels as of March 1, below analysts' expectations for 7.099 billion bushels, according to quarterly estimates by the U.S. Department of Agriculture released on Monday.
In a separate report, the USDA said corn plantings were forecast to fall 4 percent to 91.7 million acres, 1 million below the average trade forecast as farmers switch to soybeans and other oilseeds this spring.
"I think there's more bullishness for corn going forward on the back of both the stocks and plantings reports. I expect it to test the resistance level of $5.20," said Vanessa Tan, an investment analyst at Phillip Futures.
Soybeans also extended gains from the prior session, with the May CBOT contract reaching a contract high of $14.81-3/4 per bushel. It was last up 0.8 percent at $14.75-3/4, building on a 1.9 percent increase overnight.
U.S. soy supplies remained tight as of March 1 when stockpiles stood at 992 million bushels. While the number topped analysts' expectations, it was down from 998 million bushels a year earlier.
That supported old-crop futures but new-crop prices <0#S:> were weaker as the USDA predicted U.S. soybean plantings to hit a record 81.5 million acres, up 6 percent from last year and suggesting a harvest above 3.6 billion bushels.
Investment bank Morgan Stanley said despite the market's initial bullish reaction, it does not expect the stocks estimate for soybeans to be able to sustain a rally in prices.
"With sales coverage in the South American crop far behind last year's levels and Chinese demand waning, we see the setup into the second half of 2013/14 as quite different from the same time a year ago.
"Moreover, above-expected soybean area of 81.5 million acres can only be interpreted as bearish for new-crop prices, particularly when weather-related planting delays could still swell that number further," Morgan Stanley said in a note.
Chicago wheat fell 0.8 percent to $6.91-1/2 per bushel.
U.S. wheat stocks were 1.056 billion bushels, above analysts' estimates of 1.042 billion bushels, the USDA said. Wheat growers indicated sowings of 55.815 million acres, down 1 percent from last year and below expectations.
Grains prices at 0705 GMT Contract Last Change Pct chg Two-day chg MA 30 RSI CBOT wheat 691.50 -5.75 -0.82% -0.58% 661.07 49 CBOT corn 502.50 0.50 +0.10% +2.13% 479.13 72 CBOT soy 1475.75 11.75 +0.80% +2.73% 1411.80 78 CBOT rice $15.59 -$0.01 -0.10% +0.48% $15.55 59 WTI crude $101.16 -$0.42 -0.41% -0.50% $101.08 59 Currencies Euro/dlr $1.379 $0.002 +0.11% +0.24% USD/AUD 0.927 0.001 +0.09% +0.25% Most active contracts Wheat, corn and soy US cents/bushel. Rice: USD per hundredweight
Reporting by Manolo Serapio Jr.; Editing by Ed Davies and Anand Basu