Does Glyphosate Reduce Yields?

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A U.S. scientist is generating buzz with his theory that increased glyphosate use might actually reduce crop yields – due to the introduction of Monsanto’s Roundup Ready crops and the widespread use of no-till farming methods.  The scientist, Don Huber, spoke at the recent Innovative Farmers Association of Ontario about his theory.

A spokesperson for Monsanto Canada was dismissive of the claim, implying that Huber’s work is not taken seriously in academic circles because it does not reflect an accurate picture.  “It’s an academic situation,” said the spokesperson, vaguely, claiming that this sort of situation was tested by the seed company, “That’s not what growers do.  Growers use the right herbicide; they use the right fertilizer; generally speaking they take every step they can to ensure they have the right environment to produce a healthy crop.”

Image: Pixomar / FreeDigitalPhotos.net

Monsanto Canada then released a stakeholder update.  “We always update our materials when there’s some sort of public comment because we know we’re going to get calls,” said the spokesperson.  The update claims that Monsanto has studied the impact of Roundup Ready seeds on manganese uptake and states that “there are several information gaps in these studies ranging from the lack of proper soil fertility to the absence of near isogenic lines.”

According to Huber, he conducted studies at Purdue University that showed that glyphosate ties up plant nutrients like manganese and zinc, among others, not only withholding them from weeds but also drawing them out of the soil.  The real impact, says Huber, “is on those soil organisms that are responsible for making a lot of our nutrients available.”  As a result, plants can become nutrient-deficient, especially in manganese.

In a research paper, Huber concluded that the effect “is as damaging to RR (Roundup Ready) crops as to non-RR (Roundup Ready) crops,” which may give you an idea of why Monsanto was quick to dismiss Huber’s credibility.

According to Huber, disease in crops has been connected to use of Roundup Ready and glyphosate.  One study found that glyphosate use was associated with increased levels of fusarium blight in wheat.

In order to counteract the effects, Huber says that glyphosate should only be used as needed, and recommends following up with nutrient application about 15 days later (so the glyphosate does not absorb them).