Following in the train of rising prices for virtually every agricultural commodity, fertilizer prices have continued to climb. Diammonium phosphate, potash, urea, sulfur and so on have all gone up.

Take diammonium phosphate [DAP], for example. In the first quarter of last year, prices averaged some $250 a ton. In the first quarter of this year, prices have gone as high as $1200 a ton. Companies that sell these products have seen their share prices rise alongside their products. Most of these will be well known to investors.