CHS Inc., the nation's largest farmer-owned cooperative, said Monday that annual profits fell 28 percent amid tougher times in its energy and agriculture businesses.

The cooperative said earnings for the fiscal year ending in August were $781 million, a decline of $302 million from 2014. Revenue declined 19 percent to $35 billion.

About half the earnings decline happened in CHS's energy business that includes oil refineries in Kansas and Montana and a vast propane distribution network. The Inver Grove Heights-based co-op cited refinery maintenance and weaker propane demand for heating and crop drying.

"Our core businesses of agriculture and energy have entered a global down cycle which affected both earnings and revenue for fiscal 2015," said CHS CEO Carl Casale in a statement.

CHS's agricultural business also had lower revenue and profits. The co-op said a decline in grain marketing earnings, foreign exchange losses, ethanol earnings and other factors contributed to the reduced profits in that segment, which represents three-fourths of the co-op's revenue.

During the year, CHS also wrote off $116 million in expenses related to the cancellation of plans to build a $3.3 billion fertilizer plant in Spiritwood, N.D. Instead, the co-op bought a large stake in an existing fertilizer company.

CHS said some business units gained. Grain margins and volumes were up, and wholesale crop nutrient margins were up, the co-op reported. Earnings for its insurance, hedging and capital units also increased slightly, CHS said.

CHS is owned by 75,000 producers, including farmers, ranchers and other livestock operators. It has 20,000 preferred shareholders and employs 11,000 people in more than 25 countries.