My experience is that once the beans are harvested they will have the same attractive level as a WalMart parking lot--great until then, but harvest usually happens before intense hunting, unless you have a slow farmer. Corn is an excellent attractant, but can be too good--they may never have a reason to leave. Great food, great cover, spend all of their time in the fields where they can be very difficult to hunt if the fields are large. If you're hunting upland southern Iowa where the fields tend to be on narrow ridge tops they don't stay in the fields as much, and you can hunt trails into the fields and field edges very successfully. In northern Iowa and southern bottom lands where fields are large, you can have some long days/evenings on the stand watching squirrels until the corn is (hopefully) harvested. We've had some years that have been lean because fields have not been harvested until after the season, giving the deer little reason to move around much. So, as food plot crops, either corn or beans would be great, the more the better. As crops serving as defacto food plots, my vote goes for corn as a hunter with hope for an early harvest so the deer are moving around and coming into the fields to clean up the leavings, but the farmer has different considerations/objectives to meet.