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 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-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
http://www.nature.com/srep/2015/150805/srep12886/full/srep12886.html

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.