U.S. fertilizer company Mosaic Co cut its third-quarter outlook for the price and sales volume of potash and phosphate on Monday, saying crop nutrient markets had softened in the wake of the breakup of the Belarusian Potash Company (BPC).

The company's shares eased 0.9 percent in New York after markets closed.

Plymouth, Minnesota-based Mosaic, the second-biggest North American potash producer, lowered its guidance on potash shipments to a range of 1.45 million to 1.65 million tonnes in the third quarter, down from 1.8 to 2.1 million tonnes. It dropped its potash realized price expectation to a range of $330 to $340 per tonne from $330 to $360.

Mosaic said the cautious tone among buyers in potash markets has spilled over to the crop nutrient phosphate as well.

It lowered third-quarter phosphate volume guidance to 2.6 to 2.8 million tonnes from 2.9 to 3.3 million tonnes. Mosaic also cut its outlook for third-quarter realized phosphate prices to a range of $430 to $440 per tonne from $430 to $465.

Mosaic pegged its third-quarter potash gross margin rate in the low- to mid-30 percent range and its phosphate gross margin rate in the mid-teens.

The breakup of BPC in July and decision by the main player Uralkali OAO to pursue a volume-first strategy weakened potash prices and caused some buyers to delay new purchases because of uncertainty. BPC was one of the world's two biggest potash trading companies, along with North America's Canpotex Ltd, owned by Mosaic, Potash Corp of Saskatchewan Inc and Agrium Inc.