Canadian based Potash Corp plans to slash 1,045 jobs across its sites in North America and Trinidad.
The nutrient giant said it aims to reduce its workforce in Canada, the US and Trinidad by 18% - representing 570 job losses in Canada and 475 cuts in the US and Trinidad.
The company revealed all three of its business areas - nitrogen, phosphate and potash - as well as corporate services, will be impacted by the reductions.
The firm blamed, among other things, a fall in demand for fertiliser in developing markets and said the move would enable the employer to respond to market conditions and reduce costs.
"This is a difficult day for our employees and our company," said Bill Doyle, president and chief executive officer of PotashCorp.
He added: "While these are steps we must take to run a sustainable business and protect the long-term interests of all our stakeholders, these decisions are never easy."
The firm said the majority of its workforce changes are anticipated to be completed in 2013, although certain positions at impacted operations are expected to remain in place through a "transitional period".
The employer also stressed, where feasible, affected employees will be offered voluntary severance packages prior to any involuntary reductions.
PotashCorp claimed the operational and workforce moves will result in lower per-tonne operating costs.
The firm said it expects potash cost savings of $15 (£9, €11) to $20 per tonne in 2014, with a targeted reduction of $20-$30 per tonne by 2016 (from 2013 levels).
In phosphate, the company anticipates an annualized gross margin improvement of approximately $10-$15 per P2O5 tonne.