CALGARY, Alberta (TheStreet) -- Agrium (AGU) is throwing stones at the window of its beloved, standing underneath the balcony, and about to speak in iambic pentameter.

The advertisement that Agrium took out in

The Wall Street Journal

Wednesday did not sound like lines from Shakespeare, however. The Canadian fertilizer company, in hot pursuit of its U.S. rival

CF Industries

(CF) - Get Report

-- which, of course, is in hot pursuit of its Sioux City, Iowa-based rival

Terra Industries

(TRA)

-- made a last-ditch effort in the advertisement to convince CF's holders to tender their shares.

The ad's headline read: "Do You Want to Receive a Premium ... or Pay a Premium?" Agrium sweetened its offer for CF last week, a bid that CF promptly rejected as low-ball. (Terra has rejected CF's advances along the exact same lines.)

As it stands, Agrium would pay $45 in cash and one Agrium share for every CF share tendered. That puts the value of the deal at $100.54 per CF share, or $4.9 billion total, based on the Tuesday closing price of Agrium's stock.

"Tendering your shares into this offer will send an unambiguous message to the CF board: the owners of CF want this deal at this price," Agrium's ad read.

It then resorted to that ancient last-ditch move: the scare tactic. "Absent the Agrium offer, we believe the value of the CF stock will decline significantly, and that could be magnified if CF executes a Terra transaction. This is CF stockholders' last chance to send the CF board a message that can't be distorted and shouldn't be ignored."

Terra, meanwhile, is preparing for its

annual meeting on Friday

, during which its shareholders will vote on a slate of directors. In its effort to wrest control of the company, CF Industries has nominated three dissidents for election to Terra's board.

Interestingly, Agrium cited the proxy advisor RiskMetrics, which has found itself tangled up in the whole three-way fertilizer love triangle. RiskMetrics recently recommended that CF shareholders do indeed sell out their CF equity to Agrium, the ad said. Last week, the advisory firm sided with CF in its battle with Terra, recommending that Terra shareholders elect CF's directors to the board at the meeting on Friday.

Agrium reiterated that it will "consider all options" if its tender offer fails, including following CF's own lead by nominating directors to CF's board, as well as "pursuing litigation."

Shares of all three fertilizer companies were in the green Wednesday morning. CF shares gained 1.6% to $85.20, Agrium 1.3% to $56.26 and Terra 0.8% to $38.27.

-- Written by Scott Eden in New York

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Scott Eden has covered business -- both large and small -- for more than a decade. Prior to joining TheStreet.com, he worked as a features reporter for Dealmaker and Trader Monthly magazines. Before that, he wrote for the Chicago Reader, that city's weekly paper. Early in his career, he was a staff reporter at the Dow Jones News Service. His reporting has appeared in The Wall Street Journal, Men's Journal, the St. Petersburg (Fla.) Times, and the Believer magazine, among other publications. He's also the author of Touchdown Jesus (Simon & Schuster, 2005), a nonfiction book about Notre Dame football fans and the business and politics of big-time college sports. He has degrees from Notre Dame and Washington University in St. Louis.