Compelling figures from the Wall Street Journal's front page story on fertilizer:

Urea, a nitrogen-carrying fertilizer, is selling for around $600 a ton, twice the price a year ago, mostly because of a steep run-up in natural-gas prices.

The price of phosphate has climbed to about $1,000 a ton, up from $365 last year, according to Green Markets, a trade publication, while the price of a ton of potash is now more than $700, up from $230.

The Journal article does not settle the question of whether fertilizer companies are gaming the market or supply just can't keep up with demand, though reporter Lauren Etter does add a new piece to the puzzle -- an obscure, century-old law in the United States designed to promote American exports allows American potash producers to essentially collude on price-setting. But the numbers are eye-opening -- in the last year, fertilizer prices have risen faster than fuel prices. If you're looking for a culprit not-named biofuels to blame for the global food price run-up, fertilizer fits the profile.