Midwest Farms and the Gulf of Mexico "Dead Zone"

Two recent newspaper opinion pieces touched directly upon the issue of and growing conventional wisdom that nutrient loading from Upper Midwest (i.e., Corn Belt) farms is leading to water quality degradation, and, ultimately, to increasing Gulf of Mexico hypoxia (causing an area of oxygen depletion or hypoxia commonly referred to as the “Dead Zone”). 
In an October 20 guest opinion piece in the Des Moines Register, Roger Wolf, Director of Environmental Programs at the Iowa Soybean Association, contends that regulating nitrogen fertilizer application would not significantly reduce nitrate loading to Iowa waters, a position advanced recently by Iowa Governor Chet Culver and in an October 11 Des Moines Register editorial, "Will Iowans Accept Dirty Water?"  Wolf puts forth several arguments that he suggests support his conclusion.
In today’s (October 21) New York Times, the Times’ Editorial Board opined that, “Every year, usually beginning in late spring, an oxygen-depleted dead zone forms in the Gulf of Mexico at the Mississippi River’s mouth, killing off fish, shrimp and other marine life. By the time cooler weather restores life to the zone, the fishing industry has sustained substantial losses.
“Scientists have long known that the dead zone . . . is created largely by nitrate washed downstream from fertilized fields as far north as Minnesota. A study in the Journal of Environmental Quality by scientists from Cornell University and the University of Illinois has now conclusively identified the largest source of that nitrate: tiled farm fields.”
However, the opinion piece goes on to note that “Mark David, a University of Illinois researcher, observed that ‘farmers are not to blame.’ We agree. Tiling is as old as Midwestern farming. What’s needed now is more research and direct incentives from the Agriculture Department to find ways to mitigate this problem.  These include: restoring wetlands, where possible; growing cover crops to absorb water in the spring, when runoff is heaviest; different methods of applying fertilizer; and even methods of treating the runoff before it reaches creeks and rivers. Sacrificing life in the gulf for corn in the fields is a trade-off that has to stop.”