* Mosaic, Potash Corp sink after Russia quits top potash cartel
* Pfizer earnings, Aetna profit beat expectations
* Sprint reports wider loss but revenue rises; stock up 3 pct
* Dow up 0.1 pct, S&P 500 up 0.2 pct, Nasdaq up 0.7 pct
By Alison Griswold
NEW YORK, July 30 (Reuters) - The S&P 500 rose on Tuesday after earnings from Pfizer and others supported the market, but Mosaic and other potash producers tumbled on expectations of a global price decline.
Mosaic Co stock was the S&P 500's biggest percentage decliner, falling 20 percent to $42.39 after Russia's Uralkali dismantled one of the world's largest potash partnerships by pulling out of a venture with its partner in Belarus, a move it expects will cause global prices to plummet 25 percent. Mosaic's slide curbed the S&P 500's gain.
Shares of Pfizer, the largest U.S. drugmaker, rose 0.9 percent to $29.81, helping both the Dow and the S&P 500 advance after the company reported results. Pfizer's second-quarter earnings slightly exceeded estimates as the company lined up a business split that could lead to the spinoff of its generics division.
Goodyear Tire & Rubber shares surged 10 percent to $18.75 after earlier hitting nearly a five-year high of $19.60 after the company's quarterly profit more than doubled. Goodyear cited lower raw material costs and stabilizing sales in Europe as major reasons for its jump in profits. The stock was among the S&P 500's best performers.
All three major U.S. stock indexes rose and the S&P 500 came within about 7 points of the 1,700 mark earlier in the session. Seven of the benchmark S&P's 10 industry sector indexes rose, with info tech leading the gains.
"Earnings are better than fears leading up to the earnings season" had indicated they might be, "but we're close to a new high and with appropriate valuations," said Jack de Gan, chief investment officer at Harbor Advisory Corp in Portsmouth, New Hampshire.
"We're up against 1,700 on the S&P so it would take a lot to make it move substantially higher," he said.
"The nearest things on the horizon are the Fed meeting and the jobs number so I think we're going to tread water here until that."
Investors will eye the Wednesday statement from the Federal Reserve for any additional hints of when the central bank may begin to pare its $85 billion a month in bond purchases. Volume could be light in advance of the statement, which is expected at the end of a two-day policy meeting of the Federal Open Market Committee.
The Dow Jones industrial average gained 12.06 points, or 0.08 percent, to 15,534.03. The Standard & Poor's 500 Index added 3.20 points, or 0.19 percent, to 1,688.53. The Nasdaq Composite Index rose 25.24 points, or 0.70 percent, to 3,624.38.
The shakeup in the potash sector gave investors a reason to dump some of those stocks, with the selloff limiting the S&P 500's advance.
Shares of Intrepid Potash plunged 30.7 percent to $13.49 while U.S-traded shares of Potash Corp fell 20.4 percent to $30.17 and Agrium lost 4.5 percent to $87.35.
The S&P materials index was among the worst performers of the 10 industry groups, down 0.7 percent.
With results in from 60 percent of S&P 500 companies, 67.4 percent have exceeded earnings expectations - in line with the average beat over the last four quarters. About 55 percent of companies have topped revenue expectations, more than the 48 percent of revenue beats in the past four earnings seasons but below the historical average, Thomson Reuters data showed.
Coach Inc shares dropped 8.2 percent to $53.09 after the leather goods maker reported soft sales at its North American stores and announced the departures of two more executives. The stock was among the S&P 500's biggest percentage decliners.
In contrast, U.S. health insurer Aetna Inc reported better-than-expected earnings in the second quarter as medical costs in its employer-based and commercial business remained low and it closed on its acquisition of Coventry Health Care. Aetna's stock rose 0.2 percent to $63.52.
Mobile service provider Sprint Corp posted a wider quarterly loss on costs from shutting down its Nextel network, but revenue grew as customers spent more on wireless services. Sprint's stock jumped 3 percent to $5.91.