Diesel Prices Hit Record High, Threatening Farm Profits Ahead of Harvest

Record-breaking diesel prices are hitting farmers ahead of harvest, adding to their expenses at one of the most fuel-intensive times of the year.

The national average price of diesel reached $6.05 per gallon on September 11, a record high and a significant increase from an average of about $3.75 per gallon in September 2025, a rise of more than $2.30 per gallon or roughly 61%.

For a typical Midwest corn and soybean harvest operation, this increase adds up quickly: a combine may burn 12 to 18 gallons of diesel per hour, while a tractor and grain cart can use another six to 10 gallons. Adding two semis hauling grain, the total operation can consume roughly 24 to 40 gallons of diesel every hour.

At last September’s $3.75 average, that would amount to about $90 to $150 in diesel per hour. At today's $6.05 average, the same operation would burn approximately $145 to $242 worth of diesel every hour, an increase of roughly $55 to $92 for every hour of harvest.

For farmers who had begun to see some improvement in crop prices, this added expense is particularly challenging. Bradley Guse, director of BMO's Agribusiness Group, noted that the rise in diesel fuel will 'probably eat up what was able to be made there in the margins.' Higher diesel prices also extend beyond the field, affecting transportation costs throughout the agricultural supply chain.