Dye

if that is true, then the refineries already know this, have reduced the amount of red dye diesel they've recently produced based on seasonal demand, which would mean that there's not that much red dye diesel available, which makes this whole exercise more or less pointless.

Depends on what kind of farming you're doing. Ranchers need fuel year round. Citrus fruits harvest in the winter, greens, broccoli, cauliflower, brussel, cabbages, root vegetables, and alliums are winter harvest crops in some regions, and potatoes and sweet potatoes are harvested in late-autumn.