It is no surprise that trade disputes and low commodity prices have farmers worried, but researchers at Purdue University say the worry runs bone deep.

The university's Ag Barometer, a monthly index of data collected from farmers reflecting the health of the agricultural economy, dropped from 143 to 117 from June to July, the 26-point drop the largest in the index's three-year history.

Results over 100 are considered positive, however.

More than 70 percent of respondents to the survey expected to report a decline in net income of at least 10 percent this year. More than two-thirds of respondents said that trade conflicts, especially the tit-for-tat tariff hikes with China, were to blame.

China, the world's largest soybean market, put a 25 percent tariff on U.S. soybeans last month in retaliation for tariffs the Trump administration put on billions of dollars worth of Chinese goods. Soybeans are the most valuable U.S. export to China. Due to the tariffs, China cancelled future orders for U.S. soybeans, which sent prices into a nosedive.

And it's been a steep nosedive: Soybean prices have fallen about 20 percent since early June, and about 25 percent from its 52-week high.

"We can't even sell at the price of production," said Delaware County farmer Bret Davis, who is also a board member of the American Soybean Association. "That means you've got one crop you're not making a dime on."

Financial-services and credit-rating firm Moody's is also raising the alarm that the trade war with China will undermine parts of the agricultural sector reliant on exports.

Moody's highlighted Iowa, Kansas and Nebraska as being especially at-risk, but while Ohio's economy is less reliant on trade with China, Ohio's farmers do export about $1 billion worth of soybeans each year.

"The U.S. trade dispute with China will weaken the economies of states that are highly dependent on agriculture," said Marcia Van Wagner, Moody’s vice president, in a research note, "and compound already troubled agriculture sectors that have suffered from commodity price declines since 2014."

Although China doesn't buy much corn from the U.S., the American farm staple hasn't been much help as profits from soybeans have disappeared.

Booming corn harvests the past several years on top of a lack of growing export markets has corn trading at well below $4 a bushel, which many consider the break-even mark. In the Purdue research, a lot of farmers believe corn is headed even lower.

"Commodity prices dropped sharply in June and July, and there is real concern among producers that those prices will remain low and, possibly, fall even further," said Jim Minert, director of Purdue's Center for Commercial Agriculture, in a press release.

A full 40 percent of the respondents to the Purdue survey think that if the trade war continues, corn will fall below $3.25 a bushel and soybeans below $8 a bushel. Both marks would be devastating.

Compounding the issue is that, for most farmers, beans are part of a rotation system in which farmers grow corn in a field one year, then beans the next for better results and soil health. Ohio's farmers don't have a ready alternative to soybeans, which they'll likely lose money on, if the trade war continues.

"Beans could just fall right off the map," Davis said, "and the problem is, in a rotation, you have to put some beans in."

The administration has floated some help for farmers. The U.S. Department of Agriculture proposed $12 billion in aid to farmers affected by the trade war. The details of how the money would be dispersed has not been hashed out, Davis said.

"They don't have a good handle on the payment," Davis said. "We thanked them, but this is a Band-aid and we're bleeding pretty good right now."