If you are from Iowa you will feel a satisfying sense of familiarity with this virtual
crop page. Whether or not you are so privledged, take a look at the dominant habitat of
this region:
It all starts in the spring when farmers plant corn and soybeans. Below is a site scale
look at corn that has been slot-planted (no-till) into soybean residue from the previous
season's crop. This is the dominant crop rotation of Iowa: corn followed by soybeans, ad
infinitium. Notice the very healthy infestation of horseweed in this field, an early
emerging Composite Family weed that thrives in no-till fields.
Soon after planting, the little corn and soybean seedlings emerge (below). On the left are two healthy corn seedlings with enough vigor to push the large dirt clod out of the way, nice microsite don't you think? On the right are some soybean seedlings that are not doing as well. They are showing injury from the herbicide acifluorfen, notice the necrosis and lesions on the cotyledons; another nice microsite despite the injury.
Lets look at two corn fields at a different spatial scale below: field scale views of a
corn field. Both are very weed-free.
The hallmark of the corn-soybean habitat is weed infestations. Below left is some
volunteer corn towering over a site in a soybean field. Corn can be either a crop or a
weed depending on your point of view, in this picture we are not talking about a companion
crop of corn.
Below are two really weedy fields. The one on the left is a corn crop in the fall that
someone left unharvested, and the wild carrot has taken advantage of the opportunity. Like
many Michigan farmers that work in auto factories as well as farm, they would rather have
good pheasant hunting than the cash from the grain. On the right is a soybean field with
volunteer corn and a nice mat of field bindweed. The bindweed looks like it would make a
nice living mulch, but looks can be deceiving.
Below is my friend Clarence south of Madrid, in Boone County, Iowa interrow cultivating
the head rows of a soybean field adjacent to a corn field. Ten years ago you would see
many more Iowa acres being cultivated than you see today, too bad.
