NEW YORK (TheStreet) -- Fertilizer stocks will not be denied.

Shares in the sector were jumping again Friday on bullish sentiment and in the face of a few skeptical research reports issued by analysts at bulge-bracket Wall Street firms in recent weeks, including

Citigroup

(C) - Get Report

and

Goldman Sachs

(GS) - Get Report

.

The analysts' basic argument came down to valuation: fertilizer shares, which have more than doubled since last summer, vastly outperforming the

S&P 500

, had grown too pricey -- even amid the current farm boom -- and were bound to cool off, according to the Goldman and Citi sell-siders. And, indeed, fertilizer stocks have slipped over the last few weeks from the 52-week highs they reached in February.

>>Mosaic's 'Phos-Fate': Florida Mine Battle Looms

But investors were buying again on Friday.

CF Industries

(CF) - Get Report

led the gainers, advancing 5% to $132.01 midway through the session after earlier touching $133.05. The company produces nitrogen-based crop nutrients, which are vital to the cultivation of corn, the hottest of the hot consumable commodities. Since last year, supply shocks and tight supplies have driven prices for maize to new heights.

On Friday morning, corn futures rose sharply as traders reacted to the annual spring weather forecast from the National Ocean and Atmospheric Administration, which warned that "major flooding" in the Midwest will likely get worse as the season moves on.

Also driving corn prices Friday was speculation that China would increase imports of corn from the U.S. But, later on in the session, the May corn contract, the most heavily traded on the Chicago Mercantile Exchange, turned into negative territory after earlier rising as high as $7.17 a bushel.

Meanwhile, farmers remain motivated to plant lots of corn and are happy to use their fat wallets to buy fertilizers. Prices for nitrogen-based nutrients have risen sharply. Urea, for instance, has risen to about $400 a short ton from $323 in the fourth quarter. Other nitrogen fertilizers have seen similar jumps. For CF, assuming the company produced at full-out capacity this year, those price increases would mean another $1.7 billion in annual revenue.

Other fertilizer stocks were popping as well on Friday.

Potash

(POT)

was gaining 3.7% to $57.72,

Mosaic

(MOS) - Get Report

was rising 3% to $79.89, and

Agrium

(AGU)

was advancing 1.7% to $90.86.

The next significant date on the ag-stock calendar comes next Thursday, March 31, when the USDA issues its widely-watched 2011 crop forecast.

-- Written by Scott Eden in New York

RELATED STORIES:

>>Mosaic CFO Talks Cargill, Potash, China

>>Mosaic's 'Phos-Fate': Florida Mine Battle Looms

>>Ag Stock Losers: CF Industries

>>Potash Lifts Guidance as Profit Tops Views

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