(Recasts, updates with closing prices)
By Mark Weinraub
CHICAGO, March 7 (Reuters) - U.S. corn, soybean and wheat futures rose for the fourth day in a row on Monday, supported by a round of short-covering after regulatory data released on Friday afternoon showed that speculators had built the biggest net short on record in all three commodities.
But prices closed well off their session highs as ample global supplies weighed on the market. Traders also said that farmers booked sales of corn and soybeans when the market peaked, leading to a round of commercial hedging that pressured prices.
At 10:27 am. CST (1627 GMT), Chicago Board of Trade soft red winter wheat for May delivery settled up 2 cents at $4.62-3/4 a bushel.
The Commodity Futures Trading Commission's weekly commitments of traders report released on Friday showed that large speculators boosted their bearish bet in corn to 247,113 contracts. Their net short in soybeans was expanded to 135,044 contracts and their net short in soft red winter wheat raised to 149,226 contracts.
Some concerns about the U.S. Plains' crop emerging from dormancy earlier than usual because of warm temperatures added support to wheat. The advanced development leaves wheat in that key growing area vulnerable to damage if the weather turns cold again.
Dry conditions in parts of Nebraska, Kansas, Colorado, Oklahoma and Texas also added strength to the wheat market.
"The continued very warm and dry conditions will further reduce soil moisture and will increase stress on wheat as spring growth accelerates," said Don Keeney, senior agricultural meteorologist for MDA Weather Services.
CBOT May corn rose 3/4 cent to $3.59 a bushel, while CBOT May soybeans gained 3 cents to close at $8.81-3/4 a bushel.
Slow movement of crops out of Argentina and Brazil because of rain in those key exporting countries added to the strength in both corn and soybeans.
Some traders said the recent price declines improved prospects for U.S. supplies on the export market.
The U.S. Agriculture Department said on Monday morning that weekly corn export inspections rose to a better-than-expected 953,062 tonnes in the latest reporting week from 739,488 tonnes last week.
Soybean export inspections rose to 1.067 million tonnes, near the high end of market forecasts, from last week's 1.055 million tonnes.
Additional reporting by Colin Packham in Sydney and Gus Trompiz in Paris; Editing by Marguerita Choy and Peter Cooney