The price of nitrogen-based fertilizer is soaring in the United States. In just a few months urea prices have jumped as much as 50 percent. There are two main reasons. The first: Most commercially available nitrogen-based fertilizer is originally derived from natural gas, or methane, and natural gas prices have been rising steadily this year. The second: Corn cultivation requires oodles of nitrogen, and the acreage of farmland devoted to corn in the U.S. this year has jumped dramatically. When the cost of production of a commodity and the demand for it rise at the same time, you've got trouble.

Irony No. 1: As we are all well aware, the increase in corn production is directly connected to government mandates that are, at least theoretically, designed to decrease U.S. dependence on foreign oil. So a policy designed to reduce consumption of one fossil fuel -- oil -- is resulting in increased demand for another -- natural gas.

Irony No. 2: One of the best natural sources of nitrogen are legumes -- plants that can "fix" the nitrogen so abundant in the atmosphere and add it to the soil. Soybeans are legumes, which is one reason why American farmers have traditionally been fond of alternating corn and soybeans year after year in the same fields. But this year, soybean acreage is plummeting, as farmers replant corn in the same fields where it grew the previous year, and otherwise switch away from soybeans altogether, lured by the irresistible seduction of $4-a-bushel corn.

Irony No. 3: Another excellent natural source of nitrogen is chicken shit. But chicken shit is also becoming scarce in some regions of the U.S. due in part to its popularity with organic farmers.

Moral of the story? Next time the chickens come home to roost, don't waste any time collecting their excrement. There's a bright future in chicken poop.