U.S. grain and soybean futures tumbled lower Friday, as traders continued to shed risk on the uncertainty over global economic growth and fears of slower commodity imports to Japan.

Chicago Board of Trade soybeans for May delivery settled down 21 cents, or 1.5%, to $13.34 1/2 a bushel, while corn for May delivery settled off 18 1/2 cents, or 2.7%, at $6.64 1/4. Futures for soft red winter wheat for May delivery settled 21 3/4 cents, or 2.9%, lower at $7.18 3/4 a bushel.

U.S. corn futures led the slide in grain futures, dropping to their lowest level since January, as traders reduced risk exposure while assessing demand following the earthquake in Japan, the top importer of the grain.

Japan is a significant market for U.S. corn, and the uncertainty surrounding how long the effects of the earthquake would slow Japan's grain imports added momentum to extend corn's weeklong selloff, said Dan Basse, president, AgResource Co., an agricultural advisory firm.

The U.S. Grains Council said Friday's earthquake and subsequent tsunami may have caused significant damage to many of Japan's agricultural facilities and production areas, and it will likely affect grain trade.

"It is too early to tell what effect this will have on Japan's agricultural sector, but it could be of significance," said Tommy Hamamoto, USGC director in Japan.

Broad-based weakness across commodity markets helped pin grain and soy futures in negative territory. Political unrest in the Middle East and North Africa applied additional pressure to encourage investors to sell off riskier assets such as grain and soybean futures.

The uncertainty surrounding economic growth, and how it affects grain and soy demand, make commodity markets less attractive to investors.

Traders also had little news to support buying following Thursday's U.S. government forecasts for increased global supplies of grain and soybeans.

Wheat futures also tumbled on concerns about Japan, with the nearby contract at CBOT closing at its lowest level since November.

Japan routinely issues tenders to buy wheat and makes purchases from the U.S., the world's top wheat exporter. The country was expected to import 5.2 million tons of wheat in the marketing year that ends May 31, about 4% of total global imports, according to the U.S. Department of Agriculture.

Soybean futures slid, garnering further pressure from projections for big soybean harvests in South America, easing concerns about low global soy supplies. Soybean futures encountered a lot of end user buying, but not enough to offset the weight of traders reducing risk in the face of global economic uncertainty, said Basse.

Other Markets

On Friday, soymeal for May delivery fell $3.70, or 1%, to $350.00 per short ton at the CBOT. Soyoil for May delivery lost 1.03 cent, or 1.8%, to 55.90 cents a pound.

Ethanol for May delivery slumped 5.8 cents, or 2.3%, to $2.436 per gallon, while oat futures for May delivery lost 5 1/2 cents, or 1.5%, to $3.50 1/2 per bushel at the CBOT. Rice for May delivery slid 4 cents, or 0.3%, to $13.01 per hundredweight.

Hard red winter wheat for May delivery dropped 14 cents, or 1.7%, to $8.23 a bushel at the Kansas City Board of Trade. Hard red spring wheat for May delivery fell 19 1/4 cents, or 2.2%, to $8.58 1/2 at the Minneapolis Grain Exchange.