Surreal illustration of chemical spill affecting soil ecosystem.

The Unseen Impact: How Glyphosate Affects Soil and What You Can Do

Soraya Malik in Climate & Environment August 2025 • 5 min read.

"Discover the hidden effects of glyphosate on agricultural soil, microbial activity, and long-term environmental health. Learn practical steps to mitigate these impacts and promote sustainable practices."

In recent years, the intensive use of herbicides, particularly glyphosate, has raised significant environmental concerns. Glyphosate [N-(phosphonomethyl) glycine], a broad-spectrum, non-selective herbicide, is commonly used in agriculture. However, its effects on soil microorganisms and overall soil health are increasingly under scrutiny. Understanding these impacts is crucial for promoting sustainable agricultural practices and maintaining environmental balance.

A recent study investigated the effects of glyphosate on microbial populations, dehydrogenase activity, and soil respiration. The research highlights how different concentrations of glyphosate can alter soil composition and microbial activity, which are vital for nutrient cycling and overall soil quality. The study underscores the importance of considering the long-term consequences of herbicide use on soil ecosystems.

This article delves into the findings of this research, providing a comprehensive overview of how glyphosate affects soil. We will explore the specific impacts on microbial populations, enzymatic activities, and soil respiration, offering insights into what these changes mean for agricultural sustainability and environmental health. Furthermore, we will discuss practical steps that can be taken to mitigate these negative effects and promote healthier soil ecosystems.

The Impact of Glyphosate on Soil Microbial Activities

Surreal illustration of chemical spill affecting soil ecosystem.

The study revealed that soils with a history of glyphosate use exhibit significant increases in heterotrophic bacterial populations. This indicates that bacteria adapt to utilize glyphosate as a nutrient source, enhancing their growth. However, this increase in bacterial populations can also alter the soil's natural microbial balance, potentially affecting other essential soil processes. The research also found that bacterial populations were more responsive when glyphosate was present as a phosphorus source compared to nitrogen or carbon sources, highlighting its specific role in microbial nutrition.

Furthermore, the application of glyphosate led to a notable increase in dehydrogenase activity, an indicator of microbial activity. Dehydrogenase enzymes are crucial for the oxidation of organic matter in the soil, reflecting the overall biological activity. While increased dehydrogenase activity might seem beneficial, it can also indicate a shift in microbial communities and their metabolic processes. However, at very high concentrations (500 mM), glyphosate exhibited an inhibitory effect, suggesting that excessive amounts can be detrimental to soil microbes. Specifically, this study found:

Significant increase in heterotrophic bacterial populations in soils with a history of glyphosate use.
Enhanced bacterial growth when glyphosate is used as a phosphorus source.
Increase in dehydrogenase activity with glyphosate application, indicating higher microbial activity.
Inhibitory effects at high concentrations (500 mM) of glyphosate, reducing microbial activity.

Soil respiration, another critical measure of microbial activity, also showed changes with glyphosate application. Respiration rates increased with lower concentrations of glyphosate (up to 50 mM), indicating enhanced microbial metabolism. However, similar to dehydrogenase activity, higher concentrations (500 mM) inhibited respiration, suggesting a toxic effect on the soil microbes. These findings underscore the complex relationship between glyphosate application and soil health, where moderate use can stimulate microbial activity, but excessive use can lead to detrimental effects.

Moving Towards Sustainable Soil Management

The research emphasizes that glyphosate application can significantly alter soil microbial activity and populations. Increased microbial activity can be both beneficial and detrimental to plant growth, soil microbial ecology, and overall soil quality. While moderate glyphosate use might enhance nutrient availability through increased mineralization, excessive use can disrupt microbial balance, sequester plant nutrients, and increase susceptibility to diseases. Therefore, adopting sustainable soil management practices is crucial to mitigate the adverse effects of glyphosate. This includes exploring alternative weed control methods, reducing herbicide dependency, and promoting soil health through organic amendments and crop diversification. Future studies should focus on understanding the specific plant-microbe-soil interactions to develop more targeted and environmentally friendly agricultural practices.

About this Article -

This article was crafted using a human-AI hybrid and collaborative approach. AI assisted our team with initial drafting, research insights, identifying key questions, and image generation. Our human editors guided topic selection, defined the angle, structured the content, ensured factual accuracy and relevance, refined the tone, and conducted thorough editing to deliver helpful, high-quality information.See our About page for more information.

This article is based on research published under:

DOI-LINK: 10.5897/ajb11.2440, Alternate LINK

Title: The Effect Of Glyphosate Application On Soil Microbial Activities In Agricultural Land

Subject: Agronomy and Crop Science

Journal: AFRICAN JOURNAL OF BIOTECHNOLOGY

Publisher: Academic Journals

Authors: Mozhgan Partoazar

Published: 2011-12-21

Everything You Need To Know

How does glyphosate impact bacterial populations in soil with a history of its use?

Glyphosate applications in soils that have a history of its use lead to a notable rise in heterotrophic bacterial populations. This occurs because these bacteria can utilize glyphosate as a nutrient source, particularly when it's available as a phosphorus source. This adaptation enhances their growth but can disrupt the natural microbial balance in the soil, potentially affecting other critical soil processes such as nutrient cycling and disease suppression. While this growth might initially seem beneficial, it can alter the soil's natural microbial balance, potentially affecting other essential soil processes.

What happens to dehydrogenase activity in soil when glyphosate is applied?

Dehydrogenase activity generally increases with glyphosate application, indicating higher microbial activity because dehydrogenase enzymes are vital for the oxidation of organic matter in the soil. However, this increase should be viewed cautiously as it might signify a shift in microbial communities and their metabolic processes. High concentrations of glyphosate (500 mM) can have the opposite effect, inhibiting dehydrogenase activity and harming soil microbes.

How does glyphosate application affect soil respiration rates, and what does this indicate?

Soil respiration rates increase with lower concentrations of glyphosate (up to 50 mM), suggesting enhanced microbial metabolism. This indicates that the soil microbes are more active, breaking down organic matter and releasing carbon dioxide. However, when glyphosate concentrations reach very high levels (500 mM), respiration is inhibited, suggesting a toxic effect on the soil microbes. These changes highlight the importance of avoiding excessive herbicide use to maintain healthy soil.

What sustainable soil management practices can help mitigate the adverse effects of glyphosate?

To reduce the negative impacts of glyphosate, it's important to adopt sustainable soil management practices. This includes exploring alternative weed control methods to reduce dependency on glyphosate, using organic amendments to improve soil health, and implementing crop diversification to promote a balanced soil ecosystem. Future research should focus on understanding specific plant-microbe-soil interactions to develop more targeted and environmentally friendly agricultural practices.

Why does glyphosate have such a broad impact on soil microbial activity, and what are the implications of this non-selectivity?

Glyphosate is a broad-spectrum, non-selective herbicide, meaning it can affect a wide range of plants and microorganisms, not just the targeted weeds. This non-selectivity is why it impacts soil microbial activity and populations, as seen in the increase in heterotrophic bacterial populations and changes in dehydrogenase activity. This can lead to unintended consequences, such as disrupting nutrient cycling and increasing susceptibility to plant diseases. This highlights the importance of careful and judicious use of glyphosate to minimize unintended ecological harm.