With improved prices in nitrogen and potash, Potash Corporation of Saskatchewan Inc. (PotashCorp) reported first-quarter earnings of $50.7 million or $0.94 per diluted share. This is $0.88 higher than last year's first-quarter earnings of $0.06 per diluted share and above the company's first-quarter earnings guidance of $0.60 to $0.80 per share. The Canadian dollar was weaker than expected compared to earnings guidance, and that, along with a slightly lower tax rate assumption, contributed approximately $0.10 per share.