From the comments section of the linked article:
"I read about this study in a prominent magazine that farmers all over the Midwest receive, so the information is in the countryside. The problem with this "simple" solution is that it won't fit a vast majority of operations throughout the Corn Belt. My family farms 6,000 acres of corn and soybeans in Central IN. Like most farms in the state, we have no livestock to feed alfalfa and have no market for oats, or similar crops. So, by using your "simple" solution we would be taking 3,000 acres, essentially, out of production every year. Seeing as this study uses livestock to keep income "stable" I'm sure you can agree that this type of rotation would not work for our farm without making an unfeasible capital investment into grazing livestock.
"Like most farmers in our area we walk every acre during the growing season to determine what weed/pest pressure we have in a specific area so that we can take the necessary action only in the fields that require it. Since we are running a business, along with the environmental impact, it doesn't make good business sense to be blanket applying chemicals to fields that may not need it.
"With an increase in cellulosic ethanol, a similar rotation might be viable for us in the future. However, at this time, it's impossible to use this study to make any changes to our operation."