{"id":40119,"date":"2025-11-04T00:01:57","date_gmt":"2025-11-04T05:01:57","guid":{"rendered":"https:\/\/beyondpesticides.org\/dailynewsblog\/?p=40119"},"modified":"2025-11-03T15:08:03","modified_gmt":"2025-11-03T20:08:03","slug":"synergistic-effects-from-glyphosate-and-urea-fertilizer-magnify-earthworm-poisoning","status":"publish","type":"post","link":"https:\/\/beyondpesticides.org\/dailynewsblog\/2025\/11\/synergistic-effects-from-glyphosate-and-urea-fertilizer-magnify-earthworm-poisoning\/","title":{"rendered":"Synergistic Effects from Glyphosate and Urea Fertilizer Magnify Earthworm Poisoning"},"content":{"rendered":"

(Beyond Pesticides<\/em>, November 4, 2025) A study of earthworms published in Environmental Science & Technology<\/em><\/a> highlights how chemical mixtures can have both synergistic and species-specific effects, threatening the soil microbiome<\/a> and overall soil health<\/a>. In exposing two species, Eisenia fetida<\/em> and Metaphire guillelmi<\/em>, to the weed killer glyphosate<\/a> alone and in combination with urea, a form of synthetic nitrogen fertilizer, the researchers find enhanced toxicity with co-exposure as well as varying health effects between the two species. These results emphasize the need to test a wide variety of nontarget organisms for impacts from environmental contaminants, since species, even within the same genus or family, can exhibit vastly different effects.<\/p>\n

Glyphosate, as one of the most widely used herbicides worldwide, is highly researched, with a multitude of studies<\/a> linking the weed killer to effects on humans, wildlife, and soil ecosystems. Since simultaneous application of glyphosate and urea frequently occurs in agriculture, the effects of this mixture on earthworms are crucial for understanding the overall impacts on soil health. In exposing the two species to the individual compounds and as a mixture, the authors report increased glyphosate residues in earthworm gut contents, reduced body weight, aggravated intestinal tissue damage, sharply decreased digestive enzyme activity, and intensified gut microbiota dysbiosis<\/a>, among other health effects.<\/p>\n

In highlighting the species-specific impacts, the researchers state, \u201cBesides these same impacts, E. fetida<\/em> exhibited more severe oxidative damage and energy metabolic disorders under co-exposure, while M. guillelmi<\/em> showed greater sensitivity in intestinal tissue and microbial responses.\u201d These results, in simulating the widespread co-exposure of glyphosate and urea in agricultural soils, shows the \u201cmarkedly intensified glyphosate-induced growth inhibition and intestinal toxicity in earthworms.\u201d<\/p>\n

The authors continue, saying: \u201cCo-exposure facilitated the accumulation of glyphosate in earthworm gut contents, triggering a cascade of more severe intestinal damage, immune activation, and gut microbiota destabilization… [O]ur results highlight the underappreciated risks of such combined exposures for key soil fauna that regulate nutrient cycling and soil structure.\u201d<\/p>\n

Study Importance<\/strong><\/p>\n

As Beyond Pesticides has previously reported, healthy soil contains millions of living species that form microbiomes. Most of the biodiversity in soil consists of bacteria and fungi, and their number and type are regulated partially by predatory protists and nematodes that feed on bacteria. In working together, these tiny organisms<\/a> determine the health of the soil for plant growth. The soil microbial community is an important indicator of soil health, and pesticide residues in the soil can change its structure and promote resistance in some microorganisms. The soil microbiome requires balance, and contamination from toxic chemicals can affect the stability of the soil ecosystem with cascading impacts, ultimately, to human health. (See Daily News<\/em> here<\/a>, here<\/a>, and here<\/a>.)<\/p>\n

Recent research<\/a> published last month links pesticides, antibiotics, and nitrogen fertilizers to the extreme global crisis of antibiotic resistance, raising serious concerns about the adverse impacts of conventional (chemical-intensive) agricultural practices. In a particularly novel and significant finding, the researchers found that nitrogen is a strong driver of resistance processes. The influence of nitrogen fertilizers adds an important dimension to the role of agricultural practices in generating antibiotic resistance. Nitrogen benefits some soil microbes, but it is a stressor for many others. It increases antibiotic-resistance gene (ARG) abundance and can enhance uptake of the heavy metals cadmium and copper by crops. Other effects include reducing enzyme activity and acidifying the soil. (See Daily News<\/em> here<\/a>.)<\/p>\n

For the current study, two earthworm species are analyzed. As the authors point out, earthworms play critical roles in various key soil ecological processes<\/a>, with a wide body of science showing the toxic effects of glyphosate on earthworms. \u201c[A]n increasing number of studies have emphasized that both short-term and long-term exposure to glyphosate can reduce earthworm survival, decrease biomass, suppress reproduction, and induce oxidative damage and reproductive impairment,\u201d the researchers state. They continue, \u201cThese findings highlight the potential toxic effects of glyphosate on earthworms, which may further impair their ecological functions within soil systems.\u201d<\/p>\n

Urea is one of the most widely used nitrogen fertilizers and is often used in conjunction with glyphosate in agricultural soils. The authors note, \u201cUrea can change soil pH, nitrogen forms, and microbial communities, thereby influencing glyphosate adsorption, degradation, and persistence.\u201d (See research here<\/a> and here<\/a>.) Since fertilizers are often applied alongside pesticides, understanding how these mixtures interact and impact soil health is imperative.<\/p>\n

Methodology\/Results<\/strong><\/p>\n

In the study, E. fetida<\/em> and M. guillelmi<\/em> were exposed to soils treated with environmentally relevant concentrations of glyphosate, urea, or a combination of both for 28 days. After which, the \u201cconcentrations of glyphosate and its metabolite aminomethylphosphonic acid (AMPA) in both soil and gut contents were quantified, gut microbiota via 16S rRNA sequencing was characterized, and toxicological effects, including growth inhibition, intestinal barrier histopathology, and oxidative and energetic imbalance, were evaluated.\u201d<\/p>\n

The researchers find:<\/p>\n