Battling rain and cold, crumbling trade talks with China, and slumping commodity markets, northern Iowa farmer Brent Renner says it's a struggle to feel optimistic about the corn and soybeans he's planting.

"It's a physical and mental challenge," said Renner, a 43-year-old who farms near Klemme, a town of about 500 people west of Clear Lake.

"A lot of us think it can't get any worse, that it can only go up from here. But that's probably not a safe bet," he said.

Prospects for improved prices are dimming, experts say, with record supplies, disease sweeping through China's pig herd and cutting soy demand, and hope for a new U.S.-China trade deal slipping away.

Early Friday, President Donald Trump pushed tariffs to 25% from 10% on $200 billion in Chinese goods.

And the president is threatening to slap tariffs on another $325 billion in Chinese imports, covering everything China sells the United States.

"Farmers, particularly soybean farmers, have been the tip of the spear when it comes to Chinese retaliation, and I'm not sure they can take much more," said Kirk Leeds, CEO of the Iowa Soybean Association.

Escalating tariffs "undercut any remnants of optimism," Leeds said. "That's what's most devastating about this."

"There are some marketers who believe we could see $6 soybeans," he said, adding that he hopes prices don't sink that far.

Soybeans for May delivery were trading around $8 per bushel on the Chicago Mercantile Exchange on Friday.

Negotiations continue with China, but the country says it will retaliate, matching U.S. tariffs.

President Donald Trump tweeted Friday morning that U.S. farmers would be better off, with the government possibly buying $15 billion in goods to provide humanitarian assistance to needy countries.

U.S. Agriculture Secretary Sonny Perdue tweeted Friday that the president directed the agency to “work on a plan quickly."

In Iowa last month, Perdue said the government had no plans to provide another round of assistance to farmers.

China bought nearly $24 billion in U.S. farm goods in 2017, including $14 billion in soybean purchases. Last year, China's total farm purchases dropped to about $9.2 billion.

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The federal government already is providing up to $10 billion in direct assistance to soybean, corn, pork, dairy and other producers to offset harm caused by U.S. trade disputes with China, Mexico, Canada and other countries.

It's spending about $1.2 billion to purchase food that will go to schools, food pantries and other programs.

Tim Bardole, a Rippey farmer, said he understands the U.S. needs a stronger trade deal with China, especially to protect intellectual property.

"An agreement that is fair to both countries is really the light at the end of the tunnel that I'm hoping for," said Bardole, president-elect of the Iowa Soybean Association board.

"But there’s no question that agriculture is suffering with the way things are," he said.

President Trump's tweet Sunday, signaling U.S. tariffs on China would climb, cost Bardole about $25,000 on stored grain as prices fell.

Corn and soybean prices have fallen about 10% since April. U.S. farm income this year is projected to be $69.4 billion, about 45% below a 2013 high.

"A lot of producers are in serious financial pain. How long we can survive and handle it, I don't know," Bardole said.

"It's at a point now, everyone is hunkered down and trying to cut expenses and working to get through it," he said.

In addition to difficult trade talks with China, farmers are waiting for Congress to ratify a new deal with Canada and Mexico, the U.S.'s second- and third-largest trade partners. China is the country's largest trade partner.

Dermot Hayes, an Iowa State University agricultural economist, said the tariffs have made U.S. farm goods more expensive than its competitors' goods.

"It’s hard to damage U.S. agriculture any more than it already has because the duties in place are already prohibitive," Hayes said.

Joe Kerns of Kerns and Associates, an Ames agricultural risk management firm, said trade agreements are important, but the highly contagious African swine fever sweeping through China is the biggest factor weighing on soybean prices.

The disease is fatal to pigs, but poses no known human health or food safety risks.

"Dead hogs don't eat a whole lot," Kerns said, noting that China has about half of the world's hog population.

Corn and soybean prices could be depressed another three years before demand and supply becomes more balanced, Kerns said.

"We don’t have a light at the end of the tunnel for corn and soybean prices," Kerns said. "We’ve got more tough times ahead, more difficult times ahead."

He sees U.S. pork, chicken, beef and egg producers benefiting from China's efforts to replace lost protein production.

Hayes said U.S. pork prices have rallied since March as Canada and other countries have looked to replenish supplies that have gone to China.

"It's probably the one bright spot" in U.S. agriculture, he said. "We get some benefits from back-filling supplies. It's probably not 100%, but it's positive."

But it will take time to eat through large U.S. grain supplies, which will grow, based on government projections released Friday.

"We're in for a huge adjustment," Kerns said, adding that new trade agreements are unlikely to significantly address the oversupply problem.

And that means farmers, landowners and seed, machine and chemical manufacturers will have to adjust to lower prices for corn, soybeans and other commodities, he said.

The cost to produce a crop — from renting land to buying seed, fertilizer and other inputs — have been slow to decline, even though income has tumbled.

Kerns said news of a deal could provide a short price boost that could sweeten farmers' bottom line.

But the spike won't last long, he said. "It doesn't change the long-term fundamentals."

Renner and other farmers are looking at shifting soybean acres to corn, which offers a bigger potential for profit.

But rain-soaked fields in Iowa this spring could sandbag that idea, pushing them to soybeans, which can be planted later in the spring without yield losses.

And as his crops grow, Renner said he'll hope that trade deals or adverse weather will help push prices higher.

"I hope things turn around pretty quickly," he said. "It could break a lot of people. ... There's no other way to look at it. It's ugly."