Potato farmer Alex Docherty says “principle’’ is driving his long, stubborn fight after being charged with violating the Environmental Protection Act in 2012. Both Docherty and his brother-in-law Blake MacDonald lost their case in provincial court when Judge Nancy Orr found the pair guilty in September 2013 for cultivating a row crop on land that had a slope greater than nine per cent. The men were each fined $3,150. Earlier this year, P.E.I. Supreme Court Judge Wayne Cheverie dismissed appeals from Docherty and MacDonald. But that wasn’t enough to thwart Docherty, who is winding up his one-year term as chairman of the P.E.I. Potato Board. More