(Adds details, reasons for production cuts)

By Rod Nickel

WINNIPEG, Manitoba, Nov 23 (Reuters) - Fertilizer maker Potash Corp of Saskatchewan Inc said on Wednesdaythat it was reducing jobs and output at one Canadian mine and temporarily curtailing production at two others as the sector struggles with weak prices.

The company said it would cut production at its Cory, Saskatchewan, mine to 0.8 million tonnes a year from 1.4 million, resulting in a reduction of 100 jobs and 40 temporary positions starting in February.

Potash will also curtail production for six weeks at its Lanigan, Saskatchewan, mine starting in January and for 12 weeks at Allan, Saskatchewan, starting in February.

The changes come after potash prices fell to decade lows this year due to excessive global capacity, although they have recently improved. Potash Corp is still completing a multiyear expansion of its Rocanville, Saskatchewan, mine.

The production cuts w ill allow the company to best use output from its lowest-cost mines, including Rocanville, Mark Fracchia, president of its potash division, said in a statement.

Potash Corp shares dipped 0.8 percent in New York.

Pending regulatory approval, the company is merging with rival Agrium Inc, which also runs a Saskatchewan potash mine. (Reporting by Rod Nickel in Winnipeg, Manitoba; Editing by Chizu Nomiyama and Lisa Von Ahn)