What is the difference between regular diesel and farm diesel besides the red dye?

Here's a good place to start reading:

Fuels: United States (http://www.dieselnet.com/standards/us/fuel.html)

The main difference is sulfur content. ULSD (Ultra Low Sulfur Diesel) is the current fuel being sold and is rated at a maximum of 15 ppm (parts per million). This fuel is mandatory for 2007 and later model year engines (not necessarily model year vehicles, long story there). Prior to that we used LSD (Low Sulfur Diesel) which is rated at a maximum 500 ppm. And of course there is off road diesel which is listed as 500+ and usually dyed red or blue. Recently we have seen off road diesel below 500 ppm so the old school approach of dyed fuel is always above 500 is no longer absolute but it is important to still note.

The Difference Between Reg Diesel And Farm Deisel Is Die Price And Farmers Can Claim It As A Company Expense On There Income Tax And If You Run It In Your Vehicle You Can Be Charged And They Will Know That's What The Die Is For

DO NOT, I REPEAT DO NOT run this in your any diesel truck. The high sulfur content will cause you nothing but trouble. Will smoke like a whore and go nowhere and run like .