Herbicide-Tolerant Crops May Help Improve Water Quality

When genetically modified herbicide tolerant crops were made available a decade ago, it became possible to replace the traditionally used residual herbicides with contact herbicides like glyphosate and glufosinate. Unlike contact herbicides, residual herbicides are frequently detected in rivers, streams and water reservoir at concentrations exceeding health advisory levels.

 A study conducted by scientists from the US Department of Agriculture, Agricultural Research Service (USDA ARS) compared the relative losses of both contact and residual herbicides when applied to small watersheds planted with herbicide tolerant corn and soybean. Results of the four-year study revealed that losses of contact herbicides, associated with GM crops, in surface water runoff were much less compared to those for residual herbicides. The concentrations of dissolved glyphosate and glufosinate in the runoff were also found to be well below the drinking water standards. Glyphosate concentration was found four times less than the health advisory level compared to alachlor, a residual herbicide it can replace, which was found to be present 700 times greater than the standard.

The abstract of the paper published by the Journal of Environmental Quality is available http://jeq.scijournals.org/cgi/content/abstract/37/2/401  Read more at https://www.agronomy.org/press/releases/2008/0421/001/