Oct. 8--Minnesota's food and farm sector, once the happiest slice of the state economy, has suddenly lost its summertime exuberance, thanks to a breathtaking plunge in grain prices.

Corn and soybean prices have fallen almost 50 percent since June, with spring wheat prices down about 70 percent from their February peak. That has cooled much of the frothy speculation in the sector, to the great relief of grain users -- not to mention consumers, who face the worst food-price inflation in decades.

Yet for Minnesota's struggling economy, there's also unease about the ebbing of state's last booming sector.

"The feeling right now is bordering a little bit on shell shock," said Ed Usset, a grain-marketing specialist at the University of Minnesota. "We couldn't believe (grain prices) three months ago, and we can't equally believe how it reversed course and where it is today."

The earlier sky-high prices sent jolts through the state's huge agribusiness sector, some of them happy shocks, some painful.

Several Twin Cities firms rode the boom to eye-popping profits. Agribusiness giant Cargill, based in Wayzata, saw its annual earnings soar 55 percent. At CHS Inc., based in Inver Grove Heights, earnings boomed 43 percent.

But those pale compared to the Mosaic Co., the fertilizer giant based in Plymouth. In 2007 and early 2008, Mosaic was the golden child of Wall Street, as its share prices skyrocketed more than 700 percent.

Last Thursday, Mosaic said it earned

$1.2 billion in the quarter, a colossal increase. Yet its stock plunged, as hot-money investors soured on the commodity sector, amid worries of a global recession.

Noted a sardonic headline on the Investopedia Web site: "Mosaic Earnings Disappoint -- up only 384%"

If the commodities boom lifted some Twin Cities firms, it did likewise in parts of Greater Minnesota. Lee Egerstrom, a research fellow at the policy group Minnesota 2020, has seen several years of rising grain prices, land values and farm incomes translate into a broader, if uneven, prosperity.

"When you look at communities like Moorhead, and some of the cities in the Red River Valley, where residential real estate values haven't fallen, you realize there's a dynamic that you're not seeing here in the Twin Cities," Egerstrom said. "The Winonas, the Marshalls, the Mankatos, are all plugging along. They're all cities with diversified economic bases, but they all gain strength from the agricultural economy."

In Minnesota, net farm income soared 61 percent in 2007, to a record $156,000 average per farm.