 Friday's USDA planting estimate of 91.5 million acres of corn looks bearish on paper, but how much will harvested acres have to be adjusted for all the adverse weather we've seen? Spec opinions remain heavily bearish in corn, soybeans, and Chicago wheat. Non-commercials are net short over 325,000 contracts of all three. If some sort of bullish surprise were to happen to the markets, though, spec positions are dangerously vulnerable to short covering.