Since the economic record clearly shows that farmers and low skilled workers prosper during Democratic administrations and suffer during Republican administration they all vote Republican to make sure they remain truly screwed.
It sounds like you imply that a) farmers were always in the economic vise they are in now, and b) that they have consistently voted Republican.
I know that a) is not true; I'd like to see data that proves that b) has some basis in reality - at least before the Reagan years and the unholy alliance between the Moral Majority and the Republican Party.