CF Industries, which operates the nation’s largest nitrogen complex in Donaldsonville, is in preliminary talks with Norway’s Yara International about a possible merger that would create a mammoth player in the fertilizer industry.

The deal could lock in cheap U.S. energy prices for Yara, and open up global markets to CF Industries.

The combined company would have a market capitalization of more than $26 billion, second only to Potash Corp. of Canada. However, it would have annual sales of about $20 billion, almost three times that of Potash.

Yara International ASA confirmed the talks Tuesday, but both companies say there is no guarantee that a deal will be completed.

Shares of CF Industries closed up 5.3 percent, or $13.59, at $269.37.

Producing fertilizer is an extremely energy-intensive process and natural gas is a huge feedstock in the industry. A tie-up with CF Industries Holdings Inc., based in Deerfield, Illinois, could give Yara easier access to cheap U.S. natural gas supplies.

And merger talks between the two are occurring in the midst of a global agricultural boom.

The U.S. Department of Agriculture this month said that corn and soybean farmers will reap the largest harvest ever this year. There is an aggressive push to ramp up grain and livestock production in China, India and other developing countries around the globe.

Yara has a broad, global presence, with facilities and warehouses in dozens of countries and sales to more than 150 countries. Yara’s website shows it operates a terminal in New Orleans. The company sells technical grade urea and agriculture grade urea in the U.S.

CF concentrates on nitrogen fertilizer manufacturing and distribution. It has seven nitrogen fertilizer manufacturing complexes in the U.S. and Canada and a network of fertilizer distribution terminals and warehouses mostly in the Midwest.

CF’s Donaldsonville nitrogen complex, already the largest in North America, is undergoing a $2.1 billion expansion that is expected to be finished in mid-2016.

The Ascension Parish facility employs about 400 CF Industries employees and about 300 contract employees. It produces anhydrous ammonia, urea and urea ammonium nitrate solution, the three most-used nitrogen products. Products are shipped by pipeline, barge, rail and truck.