FARGO, N.D. — In the parched northern Plains, where the worst drought in decades has withered crops and forced some ranchers to begin selling off their herds, a cloud-seeding program aimed at making it rain would seem a strange target for farmer anger.

But some North Dakota growers are trying to end a state cloud-seeding program that’s been around for generations, believing it may be making the drought worse. Besides anecdotal accounts from decades of farming, they cite satellite images of clouds dissipating after being seeded and statistics over two decades that they say show less rainfall in counties that cloud-seed than surrounding ones that don’t.

“You watch the planes seed, you will see storms weaken,” said Roger Neshem, a 39-year-old farmer in the northern part of the state who is leading an effort to see if Mother Nature can do better on her own.

In response to the push, Republican Gov. Doug Burgum has asked the state Water Commission to review the program.

Hank Bodner, a cloud-seeding supporter who chairs the state’s Atmospheric Resource Board and the Ward County Weather Modification Authority, said opponents have no scientific basis for their doubts.

“We’ve told them that if we’re going to have a meeting to discuss this, you need to come with someone who has a PhD to tell us that we’re chasing the clouds away,” Bodner said.

While Hurricanes Harvey and Irma have been battering the Gulf Coast and Southeast with wind and water, the northern Plains have received little more than dust all summer. Almost one-third of Montana is in exceptional drought. Much of North Dakota is in severe to extreme drought, and even the least affected parts of the state are classified as abnormally dry.

The federal government has offered emergency loans to help farmers, and the state has requested a federal disaster declaration that could unlock direct disaster payments to farmers and ranchers hit by the drought.

Into all this comes cloud-seeding, which involves spraying fine particles of silver iodide and dry ice into a cloud system. It’s done by aircraft in North Dakota, but can be done by rockets or by generators on the ground.

The silver iodide causes water droplets in the clouds to form ice crystals that become heavier and fall faster, releasing rain and small hailstones — rather than larger stones that could batter crops.

More than 50 countries do it in some fashion: ski resorts use it to add precious powder to their slopes; hydroelectric companies seek to bolster spring runoff that powers generation systems; insurance companies support it to cut down on big hailstorms that require big property damage payouts.

Some environmental groups have raised questions about the environmental risk of using silver iodide, but the U.S. Public Health Service says cloud-seeding is safe and the North Dakota farmers who oppose their program aren’t doing so because of health concerns.

It was hail’s threat to small crops that spurred North Dakota to launch its program back in the 1950s. The state currently pays about $400,000 toward the program, or about one-third of the cost, and it operates in seven counties.

Most studies suggest cloud-seeding produces more rain, but it’s not clear to what extent. The state Atmospheric Resource Board points to a Wyoming study from 2005 to 2014 that reported an increase in snowfall of 5 to 15 percent “during ideal seeding conditions.” The board also cites a nearly 50-year-old North Dakota project that estimated a potential rainfall increase of 1 inch per growing season.

David Delene, a University of North Dakota professor and editor of the Journal of Weather Modification, said it’s difficult to assess the effectiveness of cloud-seeding because it’s impossible to tell how much rain would have fallen if the clouds hadn’t been seeded.

“Statistics aren’t always as good as we want because every cloud is different,” Delene said. “We’re getting positive indications the seeding is working. In order for it to be accepted, you need hundreds of cases.”

Neil Brackin, president of Weather Modification, Inc., the Fargo company that does the aerial seeding, said he doesn’t believe cloud-seeding is making the drought worse. He said he welcomes a review of the program.

“We have a good story to tell,” he said.

Neshem, the farmer, isn’t convinced.

“It should be their job to prove that it works,” he said. “They’re the ones taking taxpayer money without any proof that it’s doing anything. You have 55 years of seeding in Ward County and if you want to have a true scientific experiment, let’s do 55 years without it.”