GM Free Cymru

More evidence that glyphosate destroys soil biology

Date Added to website 9th August 2015

More evidence that glyphosate destroys soil biology

Comment from GM-Free Cymru: here are two more papers that show the role of glyphosate in the destruction of soil biological activity. We should not be surprised by this, since many other papers in the past have pointed in the same direction. Will EFSA and the other advisory bodies and regulators pay any attention? We doubt it. They have a long record of simply ignoring anything inconvenient to their central hypothesis that "glyphosate is perfectly safe because we say it is."

Glyphosate-based herbicides reduce the activity and reproduction of earthworms and lead to increased soil nutrient concentrations

Mailin Gaupp-Berghausen, Martin Hofer, Boris Rewald & Johann G. Zaller
Scientific Reports 5:12886. DOI: 10.1038/srep12886

Herbicide use is increasing worldwide both in agriculture and private gardens. However, our knowledge of potential side-effects on non-target soil organisms, even on such eminent ones as earthworms, is still very scarce. In a greenhouse experiment, we assessed the impact of the most widely used glyphosate-based herbicide Roundup on two earthworm species with different feeding strategies. We demonstrate, that the surface casting activity of vertically burrowing earthworms (Lumbricus terrestris) almost ceased three weeks after herbicide application, while the activity of soil dwelling earthworms (Aporrectodea caliginosa) was not affected. Reproduction of the soil dwellers was reduced by 56% within three months after herbicide application. Herbicide application led to increased soil concentrations of nitrate by 1592% and phosphate by 127%, pointing to potential risks for nutrient leaching into streams, lakes, or groundwater aquifers. These sizeable herbicide-induced impacts on agroecosystems are particularly worrisome because these herbicides have been globally used for decades.

Comment from GM Watch:
Environmental impacts “worrisome”, say researchers

Good soil depends on the services of earthworms. They enrich and improve soil, aerating it and making it permeable to water.

A new study (below) shows that glyphosate herbicide impedes the activity of earthworms and reduces their reproduction rate.

The study also found that glyphosate herbicide application led to massively increased soil concentrations of nitrate (by 1592%) and phosphate (by 127%), increasing the risks of nutrient leaching into streams, lakes, and groundwater.

Last year (see below) we reported on a study showing that at doses under those recommended for perennial weeds, glyphosate herbicide negatively affects the fertility of earthworms and puts them at risk of local extinction.

These studies show that farmers and growers who want to improve their soil and avoid polluting our water supplies should not use glyphosate herbicides.


Glyphosate Sublethal Effects on the Population Dynamics of the Earthworm Eisenia fetida (Savigny, 1826)

Marina Santadino, Carlos Coviella, Fernando Momo
Water, Air, & Soil Pollution
November 2014, 225:2207


Pesticides’ sublethal effects are not regularly taken into account when assessing agrochemical’s toxicity. With the objective of detecting chronic, sublethal effects of the widely used herbicide glyphosate, an experiment was performed using the earthworm Eisenia fetida as model organism. Earthworm adults were randomly assigned to three glyphosate treatments: control (no glyphosate), regular dose for perennial weeds, and double dose. Six E. fetida individuals were placed in each pot. Two random pots were taken weekly from each treatment and the number of adults, individual weight, number of cocoons, and presence and number of young earthworms were recorded. A matrix analysis was performed with the data. The matrix population model built showed that while the control population had a positive growth rate, both glyphosate treatments showed negative growth rates. The results suggest that under these sublethal effects, non-target populations are at risk of local extinction, underscoring the importance of th[ese] type of studies in agrochemical environmental risk assessment.

Comment from GM Watch:
Using glyphosate puts worms at "risk of local extinction" – study

Using glyphosate herbicide can wipe out local earthworm populations, a new study (below) shows. Even at exposures under the regular dose for perennial weeds, the earthworm population showed negative growth rates, meaning there were not enough young worms to replace the old ones as they died out. This means the local worm population could rapidly go extinct.

Given the irreplaceable work that earthworms do to keep the soil healthy, and the negative effects of glyphosate herbicide on beneficial soil microorganisms, it's no surprise that Roundup Ready crop cultivation is associated by some farmers with poor soil quality.