The global run-up in prices for commodities such as corn and wheat, a by-product of high oil prices, the ethanol boom, and economic growth in emerging markets, has created millions of winners and losers around the world. So far, we at Passport have focused on the losers—ordinary consumers, beer drinkers, gummy-bear lovers, chocolate eaters, and so on. But what about the winners?

Here's one: fertilizer companies. One of Wall Street's best-performing companies last year was Mosaic, a fertilizer producer based in Plymouth, Minnesota. Mosaic's share price quadrupled in 2007, and its latest quarterly earnings report is a barn-burner: profits are nearly tripling, net income was 89 cents per share, net sales are up 44 percent, and so on. Cereal crops, you see, require a lot of fertilizer.

As it happens, analysts are reportedly concerned about an impending shortage of potash, one of the three basic types of fertilizer, along with phosphorus and nitrogen. The world's largest exporters of potash are: Canada, Russia, Belarus, and Germany (Israel also exports a good deal of the stuff, which it extracts from the Dead Sea). According to Potash Corp., Mosaic's main North American competitor, China is now importing more potash than the United States. With the way China is growing, we know what that means: higher prices. But don't expect the potash boom to last forever. Production is expected ramp up around the world, and that could send prices back down to Earth in the next few years.