Quarterly earnings for CHS Inc. fell 30 percent largely due to crimped profit margins in its petroleum refining business.

Inver Grove Heights-based CHS, the nation’s largest farmer-owned cooperative, reported net income of $242.2 million Wednesday for its first quarter ending Nov. 30. The company’s revenue tallied $11 billion, down from $11.7 billion a year ago, primarily due to lower selling prices for grain.

CHS’ agricultural segment, which includes its grain handling, grain processing and fertilizer businesses, experienced a slight increase in earnings over last year’s first quarter. Agriculture-based businesses make up 68 percent of CHS’ revenue, with the rest coming from energy.

The company owns the Cenex brand and one refinery in Montana and most of another in Kansas. CHS also has a propane and transportation business that posted record earnings during the first quarter.

Propane demand was high in the Midwest during harvest season, courtesy of a moist corn crop. Propane is the fuel for corn dryers at farms and grain elevators. But propane was in short supply due to a sudden spike in demand, coupled with supply restrictions.