Residues of glyphosate-based herbicides in soil found to negatively affect plant-beneficial microbes

Researchers at the University of Turku, Finland, found that even very low levels of glyphosate-based herbicide residues have a negative effect on endophytic microbes associated with garden strawberry.

In a field study, researchers at the University of Turku, Finland, followed the standard agricultural practices of herbicide application and investigated the impact of glyphosate residues in soil on the endophytic microbial communities of garden strawberry. The findings were published in the Journal of Applied Microbiology.

Glyphosate-based herbicides are used to kill weeds in agricultural fields before sowing and are claimed to degrade quickly in the soil, so that agricultural crops planted after the two-week safety period are not exposed to the chemical. However, other studies have shown that this is not the case and low residues of glyphosate are found in the soil even after two weeks.

The effect of glyphosate is based on inhibition of the "shikimate pathway," a metabolic pathway for the synthesis of amino acids that is found in plants but not in animals. However, this pathway is present also in many microbes.

"Our study shows how even very low residues of agrochemicals can affect plant-associated microbes. Changes in the abundance of certain plant-beneficial endophytic microbes and the dominance of potentially glyphosate resistant bacteria can be concerning if they have consequences on plant health in the long run," says Dr. Mathew.

Source: https://phys.org/news/2023-04-residues-glyphosate-based-herbicides-soil-negatively.html