Potash, potash. All week long, it's seemed this humble fertilizer was on the tip of every trader's tongue. (Yuck!)

Why? No surprise there. When BHP Billiton (NYSE: BHP) offered to buy PotashCorp (NYSE: POT) for $130 a share, arbitrageurs quickly concluded that if a bidding war breaks out, the stock could be worth a whole lot more. But in the rush to bid up PotashCorp to $150, is it at least possible that they missed something? Like the fact that you don't have to own PotashCorp, to own potash? And that there's no reason to pay a merger premium to profit from the feeding frenzy in fertilizer stocks?

I want to say one word to you. Just one word: "Plasti ..." er, "potash"
PotashCorp may be the biggest name in potash, I'll grant you. But it's not the only way to play this commodity. It's not the only potash merger in the works. Most important to savvy investors, it's not the cheapest.

Over in Russia, you see, billionaire potash magnate Suleiman Kerimov is pondering a merger between two of his potash companies, Uralkali and Silvinit, with Uralkali surviving as the new "national champion" for potash in Russia -- a champion rolling in $2.3 billion worth of fertilizer revenues annually, yet valued at barely $15 billion.

For comparison, PotashCorp controls an annual revenue stream barely twice as large as the new-and-improved Uralkali would -- but commands a market cap nearly three times as large. Put another way, PotashCorp sells for 8.8 times annual sales, and Uralkali just 6.5. (In line with the 6.2-times-sales valuation on Canada's Intrepid Potash (NYSE: IPI).)

Um ...                                                                   
I know what you're thinking. If there's a cheap Western alternative to Potash, why risk buying into the mystery-wrapped riddle of an enigma that is Russia? And the answer is:

You probably don't want to take the risk. For one thing, while both Uralkali and Silvinit already trade on the Russian Stock Exchange (RTS), buying into them stateside requires purchasing ultra-thinly traded shares on the OTC market (where Uralkali trades as "URALL," and Silvinit preferred shares are called "SLVNF".) For another thing, less pure-potash fertilizer plays abound, and at more reasonable prices -- Mosaic (NYSE: MOS) at 3.8 times sales; CF Industries (NYSE: CF) a relative bargain at 2.4 times.

On the other hand, though, PotashCorp itself is said to be angling for a 10% (or greater) stake in Uralkali, as is Rio Tinto (NYSE: RTP). While I'm not saying you should follow their lead, the fact that they're interested in Uralkali at today's valuation does suggest there's something there, there.

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Fool contributor Rich Smith does not own shares of any company named above. The Motley Fool has a disclosure policy.