Money managers piled on long positions in Chicago Board of Trade corn and soybean futures amid worries about South American crops, according to government data Friday.

Large managed funds, including hedge funds, were net-long 210,084 CBOT corn contracts in the week ended Feb. 7, an increase of 10.5% from the prior week, according to the Commodity Futures Trading Commission.

The net position is the difference between the number of long contracts, or bets prices will rise, and short contracts, or bets prices will fall.

Money managers increased their net long soybean position by 55%, to 62,856 contracts.

The increases came amid speculation about smaller crops in Argentina and Brazil due to drought. Smaller corn and soy crops there would likely lead to increased demand for U.S. crops.

Traders have also worried recently about a cold snap in the Black Sea region that could result in fewer exports from Russia and Ukraine. Those worries weren't reflected in the CFTC's report on wheat, however, as money managers cut their net short CBOT wheat position only slightly, to 30,869 contracts.

The report reflects positions as of Tuesday, and don't include activity following the U.S. Agriculture Department's supply-and-demand report Thursday. The USDA report was considered neutral or negative for the grains markets.

Meanwhile, money managers increased their net-long position in CME lean hogs by 30% to 32,310 contracts.

In live cattle, money managers increased their net-long position by a modest 538 contracts, for a total net-long position of 86,188 contracts.

-By Ian Berry, Dow Jones Newswires; 312-750-4072; ian.berry@dowjones.com

(END) Dow Jones Newswires

February 13, 2012 08:43 ET (13:43 GMT)