As with most agricultural practices, specific herbicides are not silver bullets, especially when abused. Multiple, holistic approaches are needed for management. Overuse of any chemical, fertilizer, ingredient that is humanly applied will lead to Mother Nature arguing defensively on what actually should happen to her planet. We ultimately learn our lessons the hard way and the answer is usually a Goldilocks strategy, Not too much, not too little but just right.
The weed killer, known generically as glyphosate, is absorbed through plants' leaves and kills them by blocking the production of proteins they need to grow. At the same time, the U.S. Environmental Protection Agency considers it to have little toxicity to people and animals, and aside from the plants it's sprayed on, it's less of a threat to the environment because it quickly binds to soil and becomes inactive.
With increased reliance on Roundup, herbicide use on corn decreased from 2.76 pounds an acre in 1994 to 2.06 in 2005, the most recent year for which the U.S. Department of Agriculture has data. Spread that out over the 81.8 million acres planted in 2005, and it's a decrease of more than 57 million pounds of herbicides annually.
Farmers also found they could cut back or in some cases eliminate tilling, reducing erosion and fuel use.
But with any herbicide, the more it's used, the more likely it'll run into individual plants within a species that have just enough genetic variation to survive what kills most of their relatives. With each generation, the survivors represent a larger percentage of the species.
St. Louis-based Monsanto maintains the resistance is often overstated, noting that most weeds show no sign of immunity.
In Australia, weed scientist Stephen Powles has been a sort of evangelist for saving Roundup, calling it a near-miraculous farming tool.
Australia has been dealing with Roundup-resistant weeds since the mid 1990s, but changes in farming practices have helped keep it effective, Powers said. That has included using a broader array of herbicides to kill off Roundup resistant weeds and employing other methods of weed control.
Monday, June 21, 2010
The argument continues for environmentalists and anti-GM (genetically modified) protesters against chemical use in agriculture. David Mercer, AP is reporting on Breitbart: