U.S. farmers are absorbing record diesel prices during the peak harvest period, with costs rising for combines, tractors, trucks and other equipment as already thin margins come under pressure. The average U.S. diesel price reached $6.29 per gallon, up 68% from $3.74 a year earlier, according to Energy Information Administration data. Farmers cited fuel costs as high as $1,500 a day for one combine, while farm fuel expenses increased by $11 per acre for corn and $7 for soybeans. Higher transport costs are spreading through the food supply chain, particularly for produce, dairy and meat moved by refrigerated trucking (temperature-controlled freight transport). Analysts and farmers warned that grocery prices could rise over the coming months, while U.S. Senator Roger Marshall asked Agriculture Secretary Brooke Rollins for temporary relief and the USDA said it was examining the issue.