"And when the Republicans win, we will pass even more funding for our farmers," Trump told a standing-room-only crowd of thousands during a rally in the Heartland Credit Union Arena in Park City, just north of Wichita, Kansas.

The Harvest Fuel Relief program will use a formula to determine losses and offset increased diesel costs, with calculations similar to those used in the established Farmer Bridge Assistance program, according to a statement from the Department of Agriculture.

"This $8 billion dollar investment will help bring certainty to our farmers during this harvest so they can continue to feed our nation," Agriculture Secretary Brooke Rollins said in a statement released shortly after the president's announcement.

Diesel prices averaged $6.18 per gallon nationwide as of Oct. 12, up about $2.51 per gallon from the same time last year, according to the most recent data from the U.S. Energy Information Administration.

During an approximately 90-minute address, Trump highlighted recent policies his administration enacted to benefit farmers and rural Americans, including raising production targets for ethanol-based biofuels to the highest levels recorded, a move the president estimated would boost farm incomes in Kansas by $4 billion, collectively, per year.

He noted a recently signed waiver allowing the year-round sale of E15 gasoline could become permanent, but only if Republicans win in the upcoming midterm elections.

"If you want to see what is at stake in this election, just look at what's happening in France, a once-great nation that is being conquered, looted, and burned to the ground by migrants, jihadists, and communists who hate Christianity, and they hate, frankly, the Western civilization itself," Trump said.

"Americans are going to stand up and declare that we will defend our culture, we will protect our civilization, we will preserve our religion, our values, and our heritage, and we will never let our nation be conquered or destroyed by people that hate us."

Incumbent first-term Republican Sen. Roger Marshall, facing Democratic challenger Adam Hamilton in a race recent polls suggest is a toss-up, told the crowd his reelection would support "secure borders, a strong military, and lower taxes."

A loss would potentially allow Democrats to gain a majority and overtake consequential Senate committee positions, he said.

"If Kansas loses this Senate race, Chuck Schumer will control the Senate. Elizabeth Warren would control the Bank Committee, and Bernie Sanders would control the Health Care Committee, and Cory Booker, a vegan, would control the [Agriculture] Committee," Marshall said.

"We need a senator on the ag committee that can sort heifers and steers, not someone who doesn't know the difference between a bull and a steer."