Citing wild swings in the price of urea, one of the world's major wholesale producers of fertilizers has permanently closed a southwestern Ontario plant making slow-release fertilizers for the turfgrass market.

Agrium Advanced Technologies (AAT), the specialty fertilizer arm of the Calgary-based crop nutrient and ag retail giant, said Thursday it has "reluctantly" shut down its plant at Courtright, just south of Sarnia, effective immediately.

"It has become ever more challenging in these times of high urea volatility to secure a supply that would allow us to operate the facility profitably," Andrew Mittag, president of Brantford, Ont.-based AAT, said in a release.

Customers of the Courtright plant, which made about 68,000 tonnes of controlled-release products per year, will still receive AAT products from "alternate" company sources, Agrium said.

Among AAT's controlled-release products for the turf sector are BCMU methylene urea; nitrogen fertilizers Duration CR, Polyon and XCU; Nutralene, a combination nitrogen/methylene urea product; and Precise, a granular insecticide.

Some of the facility's 28 staff remain "temporarily" on the job to ship out remaining inventory and carry out the plant's final shutdown, the company said.

AAT also said it will "work closely with various regulatory agencies as part of its commitment to environmental stewardship" during the shutdown and dismantling process.