PLYMOUTH— One of the world’s largest fertilizer makers says it plans to cut 500 jobs globally as it deals with a significant decline in earnings.

The Plymouth-based Mosaic Co. is reporting that its first-quarter earnings are down 40 percent compared to a year ago. The fertilizer business has been plagued by low prices for several quarters.

The Star Tribune says Mosaic plans to cut 50 jobs at its Plymouth headquarters, which employs about 300.