I understand that this person had corn for delivery for this fall, Dec 2010.  Let say it is priced off the Dec 2010 corn trade.  He talked to the elevator and they said, " Yes, we have more corn coming in this fall than we can handle comfortably, (most elevators are that way).  Yes, you can store the corn and deliver it later, like July."  For example, if Dec corn is 2.00 and July 2011 corn is 2.30 the elevator will pay you the 2.30 instead of the 2.00.  It is called the carry, the difference between Dec and July.  So the farmer is picking up .30 there.  Farmer has cost of storage and interest lost on money as he is paid appox. 7 months later, July 2011 instead of Dec. 2010.

Next.  Fall delivery basis is say, -.60 at the elevator.  Why.  They don't want all that corn at once and are encouraging farms to store the corn and deliver it over time.  Jan 2011 basis might be something like .-45.  So the elevator knows that they will have room and time to handle the corn in July better than in the fall.  They will improve the basis to the farmer by .30 if I wait till July 2011 to deliver.  This make the July basis -.30 instead of the -.60 fall basis.  The farmer gains another .30 here. 

The total gain is the carry + the basis improvement = 60 cents - interest loss on the money - on farm storage cost = net gain of say .50. 

End of story.  lol.  Hope that helps.