The real danger of glyphosate isn’t just where it lands — it’s what it leaves behind.
When we think of herbicides like glyphosate (Roundup), we often picture the act of spraying—chemicals misting through the air, landing on leaves, weeds, and maybe drifting a bit too close to where children play. What we don’t often picture is the slow, invisible residue it leaves behind. Not just on the surface, but in the very soil we rely on to grow our food.
Glyphosate doesn’t simply disappear after application. While it’s marketed as breaking down quickly, the truth is more complicated. Depending on environmental conditions, farming practices, and how often it’s used, glyphosate can accumulate in soil over time—building up residue by residue, year after year.
And what happens to the soil under these conditions is a story that rarely gets told.
A Chemical That Sticks Around
Glyphosate is known to bind tightly to soil particles, which is often framed as a good thing. “It doesn’t leach,” regulators say. “It stays put.” But staying put isn’t the same as breaking down.
Studies show that glyphosate can persist in soil for weeks, months, and in some cases, even longer. The commonly cited half-life of glyphosate in soil varies widely—from as little as 2 days to as long as 197 days, depending on temperature, microbial activity, pH, and other factors. In some agricultural systems with regular spraying, there’s barely enough time between applications for residues to fully degrade.
This creates a situation where glyphosate can accumulate—not just as glyphosate itself, but also as its main breakdown product, AMPA (aminomethylphosphonic acid), which is also toxic and even more persistent in soil and water systems.
The Silent Disruption of Soil Life
Soil isn’t dirt. It’s a living, breathing ecosystem filled with bacteria, fungi, nematodes, and other organisms that support healthy plant growth. It’s what makes a seed sprout, helps roots absorb nutrients, and enables carbon to be stored underground.
So what happens when you repeatedly expose this living system to glyphosate?
Multiple studies suggest that glyphosate harms beneficial soil microbes—particularly those that support plant nutrient uptake or fight disease. It can reduce microbial diversity, disrupt fungal networks (like mycorrhizae), and interfere with nitrogen fixation in legume crops.
One 2022 review described glyphosate’s impact on soil ecosystems as a form of “microbial dysbiosis,” drawing parallels to the gut microbiome issues that can occur with overuse of antibiotics.
It’s not just that glyphosate kills weeds. It alters the biological foundation that plants depend on—sometimes in ways that take years to manifest.
Can Glyphosate Travel from Soil to Plant?
Despite being touted as “inactive” in the soil once bound, glyphosate can still be taken up by crops, particularly when sprayed pre-harvest (a practice known as desiccation) or when residues remain in the soil during germination and early growth stages.
There is growing evidence that crops—especially root vegetables and leafy greens—can absorb residual glyphosate and AMPA from the soil. While levels are generally lower than with direct spraying, this raises troubling questions: How many “residue-free” crops are quietly contaminated through their roots? Could this be a hidden pathway of exposure for both conventional and organic consumers?
And speaking of organic…
A Threat to Organic Integrity?
Organic farms don’t use glyphosate. But that doesn’t mean they’re protected from it.
Glyphosate contamination has been detected in organic grains, honey, and even wine—not because it was sprayed directly, but likely due to environmental drift, water contamination, or soil residues that linger from past land use.
In areas where organic farms sit next to conventional operations, glyphosate in soil and dust can migrate. Even legacy contamination from a time before the land was certified organic can pose a risk. Once in the soil, it may take years or decades to fully degrade, depending on site conditions.
In this way, glyphosate’s persistence in soil poses a systemic challenge to maintaining clean, organic food systems.
What About New Zealand Soils?
New Zealand has a diverse range of soil types and farming methods, but like much of the world, we’ve seen a steady increase in herbicide use—particularly glyphosate—as large-scale, low-till farming practices expand.
The Ministry for Primary Industries (MPI) does not conduct routine soil monitoring for glyphosate or AMPA. Without that data, there’s no real picture of how much glyphosate is accumulating—or how it may be affecting long-term soil health, water runoff, or adjacent properties.
It’s a case of: if you don’t look, you won’t find.
And that silence may be part of the problem.
And It’s Not Just Farms…
While much of the focus is on agriculture, glyphosate’s buildup in soil isn’t limited to rural paddocks. It’s also used around homes, schools, parks, and early childhood centres—anywhere people are trying to “tidy up” nature by killing weeds.
And that’s where things get personal.
Little kids play in the dirt. They dig, they crawl, they roll, they sometimes even eat it. And even when they don’t, it’s fingers in mouths, muddy knees, and bare feet on recently sprayed soil.
If glyphosate is building up in these everyday outdoor spaces—and if it’s not breaking down as quickly as we’ve been led to believe—then we have a very real problem. Not just for the soil itself, but for the young bodies coming into contact with it before their immune and detox systems are fully developed.
What lies beneath isn’t always just soil.
Sometimes it’s a residue of risk we’ve chosen not to measure.
Final Thought: What Are We Really Growing In?
Fertile soil is one of the most precious, non-renewable resources we have. And yet, we’re allowing it to be slowly altered—not by erosion or overuse, but by invisible chemical build-up. The full consequences may not be seen until it’s too late to reverse.
Glyphosate doesn’t just vanish after spraying. It lingers. It accumulates. And in doing so, it may be undermining the very foundation of our food system.
So the next time we talk about safe levels of glyphosate in food, maybe we should also ask:
What about the safety of the soil it grew in?
Resources & References
Understanding glyphosate’s true impact means looking beyond the label and diving into the science, the stories, and the inconvenient truths. The sources below offer a deeper look at how this ubiquitous chemical affects our soil, our food, and our future. Some come from academic journals, others from investigative journalism — all share one thing in common: they shine a light on what’s often left out of the mainstream conversation.
Beneath the Orange Fields: Impact of Glyphosate on Soil Organisms.
PAN Europe (2023)
A detailed overview of how glyphosate-based herbicides (GBHs) negatively impact soil biodiversity, microbial communities, earthworms, beneficial fungi, and long-term soil fertility.
View full report (PDF)
Adverse Impacts of Roundup on Soil Bacteria, Soil Chemistry, and Mycorrhizal Fungi During Restoration of a Colorado Grassland.
Bueno de Mesquita, C.P., et al. (2023)
A field study demonstrating how repeated glyphosate (Roundup) applications negatively affect soil microbial diversity, nutrient chemistry, and beneficial fungal relationships critical to ecosystem recovery.
View full article
Effects of Glyphosate on Soil Fungal Communities: A Field Study.
Vázquez, M.B., et al. (2021)
An investigation highlighting the impact of glyphosate on fungal biomass, species diversity, and community structure in semiarid grassland soils, underscoring potential long-term harm to soil ecosystems.
View full article
The 2020 European Union report on pesticide residues in food
European Food Safety Authority (EFSA)
This report provides comprehensive data on pesticide residues, including glyphosate and its primary metabolite, AMPA, in food products across the European Union. It offers insights into the occurrence and levels of these substances, contributing to the understanding of their persistence and potential accumulation in the environment.
View full report (PDF)
Testing Finds Glyphosate in Two Popular Oat Milks
Environmental Health Network (2023)
An investigative report revealing glyphosate residues detected in oat milk, underscoring contamination challenges for organic producers due to drift and legacy pesticide use.
View full article
The USDA Gives In: Evidence of Glyphosate in Organic
Real Organic Project (2023)
An exploration of glyphosate contamination in certified organic products, emphasizing the need for stricter organic standards and proactive measures to protect organic agriculture.
View full article
Knowledge is power — but only if we use it. If these references raise new questions for you, follow them. Dig deeper. Ask why this information isn’t front-page news. Because when it comes to glyphosate, what we don’t know — or aren’t told — can hurt us.
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