Potash Corp of Saskatchewan, the world's biggest fertilizer company by capacity, has cut its full-year profit forecast due to weak demand and lower prices.

The U.S.-listed shares of the company, reported a 79.7 percent fall in first-quarter profit, and the company announced it sees declines from last year to this year through the remaining marketing quarters.  

Potash prices have fallen sharply over the past year due to overcapacity, declining farm income and weak currencies in major consumer countries such as India and Brazil.

"Lower prices for all nutrients weighed on our performance for the (first) quarter and contributed to a more subdued outlook for the year," Chief Executive Jochen Tilk said in a statement.

Weak demand and increasing competition pushed potash prices lower in North America while a lack of new contracts in China and low demand from India impacted global potash deliveries in the quarter, the company said.

Potash Corp had said in January that it did not expect weak market conditions to improve soon, and suspended operations at its newest mine, Picadilly in the Canadian province of New Brunswick.