The maize crop in Spain, a major grains importer, is forecast to fall by 8%, the Agriculture Ministry said, although it confirmed that the wheat crop had recovered substantially from 2009.
In its latest crop progress report, the ministry did not explain why the maize crop would fall to 3.2 million tonnes.
Work on the maize harvest normally begins in some southern regions in late August but does not gather pace in the northern grain belt until October.
Save on drying costs
Many northern farmers leave maize uncut until the New Year so that it dries out naturally and they can avoid paying commercial driers.
Maize is the ingredient of choice for animal feed makers, and dealers say it is back in favour because it is no longer much more expensive than wheat, the main alternative.
Imports needed
Even with a bumper harvest, Spain has to import upwards of 10 million tonnes of grain to meet its needs.
It is currently buying maize from Argentina and Brazil, which is cheaper and more abundant than in traditional European suppliers such as France.
Wheat crop up
The ministry added that the recently completed winter cereal harvest, which is mainly wheat and barley, was up 16.9% from 2009.