Fertilizer giant Mosaic Co. said Friday that net income rose 77 percent in its fiscal first quarter to $526 million, though the results fell short of analysts' expectations.

The company reported earnings per share of $1.17 on sales of $3.1 billion, a 41 percent leap over the first quarter in 2011. But analysts who follow the company had projected earnings of $1.31 a share on average, according to Bloomberg.

Shares of the Plymouth-based company dropped $2.41 to $57.70.

Mosaic also said late Friday that it priced a public offering of 18 million shares at $57.65 a share. The shares are owned by the Margaret A. Cargill trusts and are being sold to raise money to fund the late Cargill heiress' philanthropic aims.

Mosaic said that during the fiscal first quarter, improvements in the sale of both phosphates and potash pushed the company's consolidated gross margin up 4.4 percentage points, to 27.5 percent.

Mosaic said it expects the market to remain strong, citing relatively low global stocks of grain and oilseeds, reasonable commodity prices and record farm profits.

Mosaic released only preliminary results and will issue its full earnings report Wednesday after the markets close.

DAN BROWNING