As expected, the weeds are adapting to Monsanto's herbicides, which is forcing a return to more organic forms of agriculture:
"The development of herbicide-tolerant crops has played a role in the growth of megafarms of 10,000 plus acres. That amount of land can’t be farmed unless you’re doing it from atop a sprayer and a combine. But dealing with pig weed now involves putting workers out in the fields to pull weeds by hands—pig weed is sturdy enough to “stop a combine in its track” according to the ABC News report. Handweeding isn’t feasible for these massive farms, which is why thousands of acres of land devoted to commodity crops are being abandoned in the face of the superweed onslaught.
"The Rodale article observes that mechanical cultivators—once considered an old-fashioned and outmoded approach to weed control—are making a comeback in the South as “steel in the field” becomes important again."