It is the rainy season in Mae Chaem district, Chiang Mai. The air is heavy with moisture, and the rain pattering all day has left the roads damp and slippery. The trees on either side are a lush green, and across the folds of the mountains, patches of tender, narrow-leaved seedlings are spreading over everything, even the rocky ridgelines.
It sounds like a dreamy, picturesque scene. Look closer, though, and there is nothing romantic about it. Those seedlings are feed maize, more than 100,000 Rai...