From Bloomberg:

Corn, wheat, soybean and rice futures tumbled after Japan was struck by its largest earthquake on record, threatening to curb demand from the Asian country, a major importer of U.S. crops.

Japan, the largest buyer of U.S. corn, is checking ports and grain depots for damage after an 8.9-magnitude earthquake and a tsunami that engulfed towns on the northern coast, the Ministry of Agriculture, Forestry and Fisheries said. Farmland was flooded with burning debris in some areas as the tidal surge swept inland, images from state broadcaster NHK showed.

Shiogama port, in the hard-hit Miyagi prefecture, unloads roughly 300 to 600 metric tons of wheat a month, the agency said. Japan is the second-largest buyer of U.S. wheat and rice and ranks third for soybeans, U.S. Department of Agriculture data show. Last month, grain prices surged to the highest since 2008 as rising demand and adverse weather eroded inventories.

For more, see: Crop Prices Tumble as Japan Earthquake Threatens to Erode Demand