Worn machinery causes problems you can see

摘要

THE long, narrow metal trough caught my attention at a conservation tillage show near Auburn, Ind. It reminded me of a section of old ear corn elevator frame, cut to make feeding troughs. But this was much more high-tech. The narrow trough was filledwith sand to simulate a seedbed. Farmers pressed against each side to get a good look. Then someone shouted 'here it comes!' Riding along on a track above the seedbed was an actual planter unit. It moved along at planting speed. As far as the planter unit knew, it was planting corn in a real field.