(Reuters) - Canadian fertilizer maker Agrium Inc (>> Agrium Inc.) on Wednesday reported quarterly profit and revenue that edged past analysts' estimates, helped by higher selling prices for potash.

Agrium sold 714,000 tons of wholesale potash in the second quarter ended June 30 at an average price of $210 per ton, compared with 697,000 tons at $194 per ton a year earlier.

Potash demand has been robust so far this year, helped by low prices and brisk offshore sales by Canpotex Ltd, the export company owned by Agrium, Potash and Mosaic Co (>> Mosaic Co). Canpotex signed supply contracts this month with buyers in China for shipments of 1.4 million tonnes through 2017.

However, the company's retail sales fell 1.5 percent to $5.71 billion.

Sales of nitrogen, potash and phosphate, in the wholesale business segment, were also down 3.9 percent at $848 million.

Net earnings attributable to shareholders in the second quarter ended June 30 fell to $558 million, or $4.03 per share, from $565 million, or $4.08 per share, in the same quarter a year earlier.

On an adjusted basis, the company had earned $4.09 cents per share. Analysts on average had expected earnings per share of $4.01, according to Thomson Reuters I/B/E/S.

Sales fell 1.5 percent to $6.32 billion, slightly above analysts' estimates of $6.31 billion.

Agrium, which is merging with Potash Corp of Saskatchewan (>> Potash Corporation of Saskatchewan Inc), also lowered the upper end of its full-year earnings per share forecast range to $5.25 from $5.75, citing weak nitrogen pricing environment and challenging weather conditions.

The company also maintained the lower end of its earnings forecast at $4.75 per share.

(Reporting by Divya Grover and Anirban Paul in Bengaluru; editing by David Gregorio, G Crosse)