If you would have asked me — or almost anyone else in the industry — in October what planted corn and soybean acreage would look like in the U.S. come spring 2010, almost everyone would answer the question with an increase in corn acres and a decline in soybean acres.

In spring 2009, 86.4 million acres were planted to corn and 77.5 million to soybeans. Our estimate for 2010 has been 87 million acres in corn and 76 million acres in beans.

However, two key fundamental shifts have occurred during November that now have everyone throwing darts at a wall about what might happen this spring.

Soybean acreage is going to be up in Brazil and Argentina. Even though exports have been incredibly strong — primarily to China — the anticipation of the sharp increase in acreage in South America has had everyone assuming that prices would be down and thus the encouragement to plant soybean acres this spring would be off in the U.S. That's the argument for lower soybean acres.

Now comes the wettest fall in history — and the longest harvest. A significant problem with vomitoxin, primarily in Ohio and eastern Indiana, has the grain industry still scratching its head as to the total impact.

THE HARDEST HIT is an area around Marion-Fostoria, OH, where the toxin levels are the highest at this writing. It is a serious problem for both the product and the coproduct, particularly for swine feeders. It's still early to tell how large the quantity of corn is going to be — but it is going to be significant and cannot be fed to hogs. Because of the location, this is obviously going to impact the movement of corn to the east and southeast from the eastern Corn Belt.

Of equal significance is the quality of DDGs that contain vomitoxin. At a bare minimum, the amount of DDGs in rations is going to have to be limited from this region or may not be used at all, in which case more soybean meal will substitute. This is a no-win situation.

What does this have to do with acreage? Unless the refuge from infected corn is plowed under or disked in thoroughly, there's a risk of carryover infection into next year's crop. To be on the safe side, a lot of this acreage may just go into soybeans.

Now the next fundamental change. Enormous amounts of rain in the central Corn Belt almost assures that harvest won't be wrapped up completely even by Christmas. Fall tillage work and fertilizer application is not getting done. It will then be easier for some of this acreage to go into soybeans — and not corn — come spring.

THE BOTTOM LINE

Farmers still like to plant corn over soybeans. It just looks and feels better with a lot more grain going into the hopper. Consequently, the shifts from the previously mentioned arguments will probably not be as big as some might forecast.

Nevertheless, instead of seeing an increase in corn and a drop in beans, its possible the shift could go the other way.

While the majority of farmers will make these decisions by the end of December, there will still be a considerable number of marginal acres that the decision will not be made until March. The shift will then depend on the price ratio of corn vs. soybeans. Should be an interesting year in the seed business.

Richard Brock is president of Brock Associates, a farm market advisory firm, and publisher of The Brock Report. For a trial subscription and information on Brock services, call 800-558-3431 or visit www.brockreport.com.