GREAT FALLS — Montana farmers are facing higher costs and more uncertainty after Canada imposed retaliatory tariffs on $20 billion worth of U.S. goods, including agricultural equipment, in response to tariffs from the Trump administration. The measures are landing in north-central Montana’s Golden Triangle, one of the country’s most productive wheat and barley regions. Farmers there already contend with elevated fuel and fertilizer prices, higher interest rates and commodity prices that have remained broadly flat for decades. Steve Sheffels, a wheat farmer and president of the Montana Grain Growers Association, said he is considering buying a new seed drill and grain bins made in Canada. A tariff of 15% or more on much of that equipment could put those purchases out of reach, he said. Montana’s economy is closely tied to its northern neighbor. Canada is the state’s largest trading partner, accounting for about $1 billion in cross-border sales, according to the Montana World Trade Center at the University of Montana. Canadian companies also buy Montana cattle, which are shipped north to be finished. Montana barley is often used to feed those cattle, said Brigitta Miranda-Freer, executive director of the trade center. For years, Montana producers have looked to Canada for some machinery and farm supplies, helped in part by favorable exchange rates. The new tariffs threaten to make those purchases more expensive while also putting pressure on established trade relationships. Lee Dahlman, a fourth-generation wheat farmer and cattle rancher near Dutton, said the instability is more troubling than any single price increase. “Things are more volatile,” Dahlman said. “The uncertainty is what bothers me.” Dahlman has been trying to reduce his exposure to overseas supply chains by investing in soil probiotics that could lower his fertilizer needs. He also rotates chickpeas and lentils into his fields, crops that add nitrogen to the soil and can reduce reliance on synthetic fertilizer. Sheffels has made a similar effort to control costs. Computer-guided equipment allows him to apply pesticides and liquid nitrogen more precisely, which he estimates has saved tens of thousands of dollars on farm inputs. The trade dispute is politically complicated in Montana, where voters have strongly supported President Trump. But the administration’s approach has drawn concern from farmers whose businesses depend on predictable relationships with Canada. “It’s just sad that food has to be a bargaining chip,” said Jillien Streit, director of the Montana Department of Agriculture. Streit also operates a family farm with her husband near the Canadian border. Streit has encouraged Montana producers to diversify beyond monocropping and seek regional food markets that could make them less dependent on international trade. She said the tariffs are creating serious challenges but may also prompt farmers and communities to develop new markets. Dahlman said farmers can adapt by reducing purchases from Canada when possible, but he still hopes the United States and Canada reach a stable agreement. Sheffels, whose wife is Canadian, said the deterioration in relations feels especially personal. “You don’t treat your neighbors like this,” Sheffels said.