Yes, if they cannot use their product and keep their pollution on their land (pollution in the sense that it is a byproduct of the process they are using) then they should not use it.
When a painter paints a home with a portable sprayed, if the neighbor’s home is speckled with paint, it is not that homeowners’s issue, it is the painters problem to take responsiblity for.
That elimates every step in the crop production, from tillage, to harvest. It also elimates NOT doing anything with the land. It also elimates every step in animal production.
I pointed out upthread that I think you don't even know a farmer, now I'll bet you haven't even been on a farm.