Shares of agricultural equipment maker Deere & Co. (NYSE: DE) have been plunging in early trading more than 6% despite posting a rise for its second-quarter profit, as its earnings per share were a bit shy of analysts' estimates. In addition, the company warned about further higher costs threats.

For the quarter, the world's largest manufacturer of agricultural machinery reported that its profit surged 22% to $763.5 million, lifted by soaring crop prices that increased international demand for agricultural equipment. The company posted earnings of $1.74 a share, slightly missing analysts' predictions for earnings of $1.75 per share in the quarter.

The agricultural equipment maker also announced a respectable 18% jump in revenues to $8.1 billion. Revenue during the period was helped by a 47% increase in overseas sales that benefited from the weak U.S. dollar. Analysts had forecast a lower revenue of $7.6 billion, according to Reuters Estimates.

Looking ahead, Deere forecast a growth of 20% for both its third-quarter and full-year 2008 sales. The company also sees third-quarter net income in a range of $550 million and $575 million and $2.2 billion for the full year.

So now the bad news. Deere warned it expects to face some troubles related to higher raw-material costs and the availability of various parts and components.

For the moment though, the stock is being pushed down on disappointment over its second quarter earnings figures. One analyst at Longbow Research, Eli Lustgarten, wasn't too impressed by Deere's quarterly results, saying they "didn't knock the socks off anyone and the guidance is very conservative."