We’re hearing it from farmers, gardeners, and environmentalists: earthworms aren’t as common as they used to be.
You might not think much of it — until you remember that earthworms are one of nature’s most important workers. They’re vital for soil health, nutrient cycling, and maintaining the very ground we depend on to grow our food.
So why are they disappearing?
It’s tempting to blame climate change or habitat loss. But one possible culprit keeps getting overlooked — glyphosate. The world’s most widely used herbicide might be doing more than just killing weeds. It might be killing the very organisms that keep our soil alive.
The Problem with Glyphosate and Soil Health
Glyphosate doesn’t just break down into harmless components after it’s sprayed. One of its primary breakdown products, aminomethylphosphonic acid (AMPA), can persist in the environment for months or even years, depending on factors like soil composition and temperature. AMPA binds to soil particles and, like glyphosate itself, can affect non-target organisms. While glyphosate is often hailed as a plant-specific herbicide, its impact — including through AMPA — on soil life like earthworms is becoming increasingly evident.
Researchers have found that glyphosate can harm earthworms in several ways:
- Reduced Reproduction: Studies show that exposure to glyphosate can reduce reproductive success, leading to fewer earthworm cocoons and juveniles.
- Digestive Damage: Glyphosate can disrupt the gut bacteria that earthworms rely on to process organic matter.
- Direct Toxicity: At higher concentrations, glyphosate can be directly lethal, causing physical damage and reduced mobility.
If earthworms are vital to soil health, why are we risking their decline with such widespread glyphosate use?
But Isn’t Glyphosate Supposed to Be Safe for Animals?
That’s what regulators claim. Glyphosate is said to target the shikimate pathway, which animals, including earthworms, don’t have. But just like in humans, that argument overlooks the microbial communities that do use the shikimate pathway.
Earthworms ingest soil as they move through it, breaking down organic matter and enriching the soil as they go. When that soil contains glyphosate, it’s not just the earthworms that are affected — it’s the entire microbial ecosystem within their digestive system.
Disrupted digestion means less efficient nutrient cycling, and less nutrient cycling means poorer soil health. If earthworms are the architects of fertile soil, glyphosate might just be tearing down their work.
Why Does This Matter?
Earthworms are more than just garden companions. They:
- Improve soil structure by aerating it as they burrow
- Break down organic matter into nutrients that plants can absorb
- Increase soil fertility through their waste (castings)
- Enhance water retention by creating pathways for moisture
Take them out of the equation, and soil health suffers. When soil health suffers, crop yields decline, and the entire food web becomes less resilient.
What Are We Missing?
If earthworms are disappearing, why aren’t we hearing more about it? Part of the problem is that regulators don’t require long-term studies on the ecological impacts of glyphosate. The data that does exist is often buried in academic journals or dismissed because it’s not “conclusive enough.”
And while scientists are sounding the alarm, agricultural policies haven’t caught up. We’re still spraying glyphosate on fields, parks, and roadsides — without fully understanding what it’s doing to the organisms living in the soil.
The Real Question Isn’t Just About Earthworms
It’s about the larger ecosystem. If glyphosate can harm earthworms, what’s it doing to the countless other organisms that make healthy soil possible? Bacteria, fungi, nematodes — all these invisible workers contribute to the fertility and resilience of our agricultural systems.
If we’re disrupting the very foundation of soil health, what are we really gaining by using glyphosate? And at what cost?
Final Thought
Maybe it’s time to rethink how we use glyphosate. If it’s harming the organisms that keep our soils healthy, that’s not just an agricultural problem — it’s a public health issue. We can’t afford to keep looking the other way while soil life quietly declines.
Let’s stop assuming that just because glyphosate doesn’t kill outright, it’s harmless. Sometimes the damage is quieter — but no less devastating.
Resources & References
Understanding the impact of glyphosate on earthworms is essential to grasp the broader environmental implications of using glyphosate-based herbicides (GBHs). The following peer-reviewed studies provide evidence on how glyphosate affects earthworm health, behavior, and soil ecosystems.
Glyphosate-Based Herbicides Reduce Earthworm Activity and Reproduction
Summary: This study found that GBHs significantly decreased the surface casting activity of Lumbricus terrestris and reduced reproduction by 56% in Aporrectodea caliginosa. Additionally, herbicide application led to increased soil concentrations of nitrate and phosphate, indicating potential risks for nutrient leaching.
Read the study: Nature – Scientific Reports
Effects of Glyphosate-Based Herbicides and Their Active Ingredients on Earthworms
Summary: Research demonstrated that both GBHs and their active ingredients reduced earthworm activity, including casting and movement. The study also noted increased glyphosate concentrations in soil and leachate, particularly under low soil organic matter conditions.
Read the study: Environmental Sciences Europe
Glyphosate Effects on Earthworms: Active Ingredients vs. Commercial Herbicides
Summary: This study compared the effects of pure glyphosate salts and commercial GBHs on earthworm behavior, growth, and reproduction. Findings indicated that both forms adversely affected earthworm reproduction and biomass, with environmental factors like temperature and soil organic matter influencing the severity of effects.
Read the study: MDPI Journal
Glyphosate Herbicide Affects Belowground Interactions Between Earthworms and Mycorrhizal Fungi
Summary: This research revealed that glyphosate application decreased root mycorrhization and soil fungal biomass. It also found that herbicide exposure, in combination with earthworms, altered soil water infiltration and led to increased leaching of glyphosate after simulated rainfall.
Read the study: Nature – Scientific Reports
Exposure to Roundup Increases Movement Speed and Decreases Earthworm Body Mass
Summary: This study found that exposure to Roundup® increased earthworm movement speed but decreased body mass, indicating a stress response. The altered behavior and physiology could impact soil structure and nutrient cycling, potentially compromising soil health.
Read the study: Frontiers in Environmental Science
These studies provide critical insights into the potential impacts of glyphosate on soil ecosystems, particularly concerning earthworm health and activity. Understanding these risks is essential when evaluating the broader consequences of widespread glyphosate use.
Image Source & Attribution
We’re grateful to the talented photographers and designers whose work enhances our content. The feature image on this page is by buhta. You can find more of their work here: https://www.123rf.com/profile_buhta
