This has not been a good month for the herbicide Roundup®. (You can read a brief introduction to Roundup® here.)
Briefly, the NY Times article reports on the growing concern among some agronomists and farmers that the increasing use of the herbicide glyphosate (a.k.a., Monsanto’s Roundup®) is adversely affecting croplands, sometimes leading to harder and more compact soils.
“Because glyphosate moves into the soil from the plant, it seems to affect the rhizosphere, the ecology around the root zone, which in turn can affect plant health,” said Robert Kremer, a scientist at the United States Agriculture Department, who has studied the impact of glyphosate on soybeans for more than a decade and has warned of the herbicide’s impact on soil health. (from Ref. 1 below).
Of course, Monsanto denies any such significant effects of Roundup®. Surprisingly, considering the huge amounts of Roundup® used every year, “…research detailing the adverse effects with glyphosate is limited,…“, according to the NY Times report.
As potentially bad as this news is, the other news is even worse for Roundup®.
Question: What would truly end the use of glyphosate?
Answer: When glyphosate no longer kills noxious weeds.
The emergence of populations of so-called “superweeds” that have evolved resistance to glyphosate has been previously discussed on this blog, both here and here. But, recently, this problem has gotten very much worse.
“U.S. farmers are heading for a crisis,” says Stephen Powles of the University of Western Australia, Crawley. Powles is an expert on herbicide resistance, a worsening problem in U.S. fields. Weeds resistant to glyphosate—the world’s most popular herbicide—are now present in the vast majority of soybean, cotton, and corn farms in some U.S. states. Perhaps even worse, weeds that can shrug off multiple other herbicides are on the rise.” (from Ref. 2 below)
Some might blame the widespread adoption of glyphosate-resistant GMO crops, such as Roundup Ready® soybeans, in the U.S., which has led to an increase in glyphosate applications. This, of course, has led to increased selection pressure on plants to evolve resistance to glyphosate. and, voilà, glyphosate-resistant weeds.
According to Larry Steckel, weed management scientist at the University of Tennessee’s West Tennessee Research and Education Center in Jackson, “Growers think there will be something over the horizon that will bail them out. But there isn’t.” (from Ref. 2 below)
Integrated Weed Management anyone?
1. Strom, S. (19 Sept 2013) “Misgivings about how a weed killer affects the soil.” New York Times (Full Text).
2. Service, R. (20 Sept 2013) “What happens when weed killers stop killing?” Science, Vol. 341 no. 6152 p. 1329. (Summary)
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