North America’s largest farm-owned cooperative will pay $2.8 billion for a minority stake in CF Industries Nitrogen LLC, which owns a massive fertilizer complex in Donaldsonville.

The deal provides an assured, long-term supply of nitrogen fertilizer for cooperative- and farmer-owners of St. Paul, Minnesota-based CHS Inc., said CHS President and Chief Executive Officer Carl Casale. Cooperative members will also benefit from greater efficiency and economics under the agreement.

The agreement also means CHS can buy 1.7 million tons of UAN and urea, two of the most heavily used fertilizers, at market prices each year. CHS also will be entitled to semi-annual profit distributions from CF Nitrogen.

CF Nitrogen also owns production facilities in Yazoo City, Mississippi, and Port Neal, Iowa. CF Nitrogen is owned by CF Industries Holdings Inc. The parent company expects to contribute its Woodward, Oklahoma, plant to CF Nitrogen before the CHS deal closes.

The CHS announcement comes just days after CF Industries’ $6 billion deal for the distribution networks of Netherlands-based OCI N.V. The deal will create one of the world’s largest nitrogen fertilizer companies.

Tony Will, CF Industries president and CEO, said the venture with CHS is the logical next step for his company. CF Industries previously has made long-term deals with industry leaders Mosaic Co. and Orica.

In late 2013, Mosaic signed a deal to buy between 600,000 and 800,000 tons of ammonia per year from CF Industries. The deal, good for up to 15 years, allowed Mosaic to drop its plans for a new ammonia plant at its Faustina phosphate complex in St. James Parish. Mosaic said the move would save it $1.1 billion in capital spending.

CF Industries is spending $2.1 billion to expand production capacity by 40 percent at its Donaldsonville facility, already the world’s largest nitrogen plant. The plant produces urea, urea-ammonium nitrate, or UAN, and anhydrous ammonia urea — the three nitrogen-based products most heavily used by agricultural, industrial and other markets. The Donaldsonville plant can already produce 5 million tons of those products a year.

The UAN expansion is expected to begin operating later this year, with the ammonia expansion set to come online in early 2016.

Follow Ted Griggs on Twitter, @tedgriggsbr.