Echoes of USDA's report on 1 March planting intentions and quarterly stocks estimates are still reverberating, and no doubt they will continue to do so. We all knew that old crop U.S. 2011/12 corn supplies would be tight. However, USDA's surprisingly low 1 March corn stocks (after three quarters of surprisingly high corn stocks) imply a level of tightness requiring that demand during the second half of the corn crop year somehow be constricted. Call it price rationing, if you like. The seemingly erratic series of quarterly corn stocks estimates from USDA may suggest caution about drawing hard conclusions from the latest one, but the market must play the hand it has been dealt. This explains why the spot CME May corn contract at this writi...