USDA scientist: Monsanto’s Roundup herbicide damages soil

This article was originally published in October 2011

This is an adaptation of a blog post by “Mother Jones” food writer Tom Philpott. It first appeared on in August.

Monsanto’s public relations team is facing a real headache involving one of its flagship products: the herbicide Roundup (chemical name: glyphosate), upon which the agribusiness giant has built a highly profitable empire of “Roundup Ready” genetically engineered (GE) seeds.

The problems with Roundup go beyond the “superweed” phenomenon: the fact that farmers are using so much Roundup, on so much acreage, that weeds are developing resistance to it, forcing farmers to resort to highly toxic “pesticide cocktails.”

What Roundup is doing aboveground may be a stroll through the meadow compared to its effect below. According to USDA scientist Robert Kremer, Roundup may also be damaging soil — a sobering thought, given that it’s applied to hundreds of millions of acres of prime farmland in the United States and South America. Here’s a Reuters account of Kremer’s presentation at a recent conference:

The heavy use of Monsanto’s Roundup herbicide appears to be causing harmful changes in soil and potentially hindering yields of the GE crops … Repeated use of the chemical glyphosate, the key ingredient in Roundup, impacts the root structure of plants, and 15 years of research indicates that the chemical could be causing fungal root disease, said Bob Kremer, a microbiologist with the U.S. Department of Agriculture.

Kremer has been raising these concerns for a couple of years now — and USDA has been downplaying them for just as long. When Grist journalist Tom Laskaway asked Kremer’s boss at the Agricultural Research Service, Michael Shannon, to comment on Kremer’s research, Shannon “admitted that Kremer’s results are valid, but said that the danger they represent pales in comparison to the superweed threat.”

So let’s get this straight: The head of USDA crop research agrees that Roundup damages soil and thinks the superweed problem is even more troublesome. In the face of these two menaces, you might expect USDA to intervene to curtail Roundup use. But Shannon meant his statement as a rationale for ignoring Kremer’s work. Meanwhile, USDA keeps approving new Roundup Ready crops — ensuring that the herbicide’s domain over U.S. farmland will expand dramatically.

Kremer commented on his employer’s reception of his work in a Reuters article last year:

“This could be something quite big. We might be setting up a huge problem,” said Kremer, who expressed alarm that regulators were not paying enough attention to the potential risks from biotechnology on the farm, including his own research … “Science is not being considered in policy setting and deregulation. This research is important. We need to be vigilant.”

Meanwhile, at a conference in Boulder, Colorado, in early August, another mainstream ag expert raised serious concerns about the poison. Iowa-based consultant Michael McNeill, who has a Ph.D. in quantitative genetics and plant pathology from Iowa State University, advises large-scale corn and soy farmers on weed control and soil fertility. He’s observing trends in the field that are consistent with Kremer’s research. Here’s “Boulder Weekly”:

McNeill explains that glyphosate is a chelating agent, which means it clamps onto molecules that are valuable to a plant, like iron, calcium, manganese and zinc … The farmers’ increased use of Roundup is actually harming their crops, according to McNeill, because it is killing micronutrients in the soil that they need, a development that has been documented in several scientific papers by the nation’s leading experts in the field.

For example, he says, harmful fungi and parasites … are on the rise as a result of the poison, while beneficial fungi and other organisms that help plants … are on the decline. He explains that the overuse of glyphosate … [is] leading to lower [crop] yields and higher susceptibility to disease.

According to McNeill, problems with Roundup aren’t limited to the soil — they also extend to Roundup Ready crops and the animals that eat them.

McNeill says he and his colleagues are seeing a higher incidence of infertility and early-term abortion in cattle and hogs that are fed on GMO crops. He adds that poultry fed on the suspect crops have been exhibiting reduced fertility rates.

McNeill made an interesting comparison: “Just as DDT was initially hailed as a miracle pesticide and later banned, researchers are beginning to discover serious problems with glyphosate.”

The Environmental Protection Agency (EPA) has been in the process of reviewing glyphosate’s registration since July 2009, but I’ve seen no evidence that the agency has the fortitude to challenge Monsanto and its multibillion-dollar empire.

Kremer told Reuters that neither EPA nor USDA has shown interest in further exploring his research. Maybe Monsanto’s PR team doesn’t have much to worry about, after all.

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