The tumble continues: Corn, soybean and wheat futures are all trading lower in early trading Thursday.

December corn futures are 15 3/4 cents lower at $6.27 per bushel, while January soybeans are 9 1/4 cents lower at $11.78 1/2 and December wheat is 12 1/2 lower at $6.04 1/4 per bushel, according to Barchart.com.

• See more: Corn drops to 1-month lows on poor exports

With the exception of news Thursday morning of poorer-than-expected corn export performance, the grain markets -- like other trades -- remains focused on macroeconomic worries about how the European debt crisis will be resolved, according to ICAP Energy LLC Derivatives Manager Scott Shellady.

"I think that a lot of this has to do with the reactionary global economic environment that we are in. Until we start to see some traction in the markets that is not solely news driven we will continue to see big up day and big down days without any real trend," Shellady said Thursday morning. "When we start to see real resolutions out of Europe then I think we can start to focus on individual markets and their macros instead of linking everything to what is happening elsewhere."

• See more from Shellady in Marketing Talk  
• See more of the latest grain futures prices