$3 corn will be left to dry in field longer than $5 corn, but for the most part, any corn you see standing in Dec is due to inability to get it out rather than "storing" corn in the field. Too much risk of quality deterioration.
Non traditional storage, ie bags, bunkers, hoop barns, will enable industry to handle the crop. As point of reference on how quickly storage can go up, over past couple of months, one KS Coop put in ten 1 million bu bunkers for this years corn crop. This was necessitated by a record KS wheat crop, of which much is still in storage.
As mentioned earlier, unlike past couple of harvests, both western railroads are current on rail orders, huge export programs for beans and corn, there's always local logistical issues, but there are plenty of homes for this year crop.
More than you wanted to know...