Diesel will mostly evaporate.
My favorite story about diesel from several decades ago. Crew was doing salvage on a sinking ship. They had some time but they couldn’t focus on any one thing in the cargo for too long. They noticed a bunch of furs of different colors. Some of them were really expensive but alas they deemed them all worthless because they were soaked in the ship’s diesel fuel oil. So they did the salvage on the rest and got what they could. They later found out that dry cleaning solvent and diesel fuel are nearly identical. The coats would have been just fine.
That soil is probably very sandy and most of it will soak down through.