Study: Pesticide residues found in more than two-thirds of European soils – not only in agricultural landscapes

When pesticides are discussed, the focus is usually on bees, birds, or residues in food. Less attention is paid to the place where many of their effects begin: the soil. Yet it forms the basis of our food supply and is home to billions of organisms. An international study, published in early 2026 in the journal Nature, shows how strongly pesticide residues have already altered this ecosystem.

The researchers examined how widespread pesticides are in European soils, and what consequences they have for soil life. The result is clear: pesticides are not a marginal phenomenon. They are now part of everyday life in many soils, with measurable effects on biodiversity and soil functions.

A Europe-wide soil cross section

For the study, 373 sites in 26 EU member states were investigated. The samples came from very different landscapes: from intensively used arable land to fruit and wine-growing regions, as well as extensive grassland and forests. The aim was to obtain a realistic picture of the situation in Europe, not only under laboratory conditions but in the real environment.

The researchers combined several modern methods. On the one hand, they chemically analyzed which pesticide residues were present in the soil and at what concentrations. On the other hand, they used DNA analyses to determine which organisms lived in the soil: bacteria, fungi, protozoa, nematodes, and small arthropods. In addition, they recorded genes that indicate which functions these organisms perform, such as supplying plants with nitrogen and phosphorus. This produced a detailed picture of how chemicals and soil life are linked.

Pesticides in Europe’s soils – almost everywhere

The first key result: pesticide residues were found in around 70% of all soils studied. This was especially common on arable land. But residues were also detected in forests and meadows, where no spraying takes place. They apparently reach these areas via wind, water, or from neighboring agricultural fields.

Pesticides also often remain in the soil for a long time. Many active substances and their breakdown products are only slowly degraded. This creates not a short-term burden but a persistent background load that builds up over years.

One of the main drivers of change in soils

The study also shows that pesticide residues in soil are among the strongest factors explaining why communities of organisms differ from place to place. Only basic soil properties, such as pH or humus content, had an even greater influence.

This refutes the common assumption that pesticides in soil are merely a side effect of intensive agriculture. In reality, they decisively shape soil life in many regions. Different groups of organisms respond differently. Some decline, others appear to increase temporarily. But these apparent “winners” are not a sign of a healthy system. In disturbed ecosystems, power relations often shift without the balance being maintained.

When important helpers disappear

Particularly worrying is the decline of organisms that are essential for fertile soils. These include mycorrhizal fungi, which help plants absorb water and nutrients, as well as certain soil bacteria and nematodes involved in nutrient turnover. These living organisms ensure that plants are supplied efficiently, that humus forms, and that pathogens are kept in check. When they are weakened, the soil loses part of its natural capacity.

The study also shows that pesticides in soil alter basic biogeochemical cycles. Genes important for nitrogen and phosphorus cycling are affected. This directly impacts the long-term fertility of soils.

Short-term gains, long-term damage

These results reveal a fundamental contradiction. Pesticides are used to secure yields. In the short term they often achieve this purpose. Pests and diseases are reduced, and harvests increase. In the long term, however, they damage the very biological processes that make stable yields possible. When beneficial microorganisms, fungal networks, and soil fauna decline, plants become more vulnerable to stress, drought, and disease. To compensate, more fertilizer, more pesticides, and more technical control are needed. This creates a downward spiral: the soil loses its self-regulation capacity, dependence on chemicals rises, and the system becomes increasingly unstable – a so-called “chemical treadmill.”

The new study provides the first Europe-wide evidence that this mechanism is also detectable in soil. Pesticides destabilize not only individual species but entire functional networks. What seems like a solution in the short term becomes a problem in the long term.

The authors note that the complex reality of pesticide applications – for example as mixtures, at different concentrations, and over long periods – is often not fully captured in traditional approval procedures and laboratory tests. Because precise application data are missing for each site, not all interactions of individual active substances can be clearly separated. At the same time, they emphasize that the large number of sites and habitats studied strengthens the reliability of their results, because the observed patterns repeat across national borders and do not occur by chance.

Why this matters for species and nature conservation

The study results affect not only agriculture but nature conservation as a whole. When people talk about species loss, many first think of birds, insects, or the disappearance of forests and habitats. Less attention is paid to the habitat beneath our feet. Yet a large share of biological diversity lives in the soil: billions of bacteria, fungi, protozoa, worms, and small animals form highly complex communities there that are essential for the functioning of entire ecosystems.

These organisms ensure that plants receive nutrients and water, that dead material is decomposed, that humus forms, and that pathogens are kept in check. They regulate nutrient cycles, store carbon, and stabilize soil structure. Without these processes, forests, meadows, or croplands could not persist in the long term.

Soil is therefore not a passive “substrate” for plants but a living system. If this system is damaged, the consequences do not remain below ground. When soils lose biological richness, plants lose part of their natural support. They grow more slowly and become more susceptible to drought, disease, and nutrient shortages. This affects insects that depend on these plants, birds that feed on them, and entire food chains. The loss of soil life thus triggers a chain reaction that runs through all levels of the ecosystem.

The new study makes clear that pesticides systematically alter and weaken these invisible communities. They therefore attack not only individual species but the fundamental processes on which biodiversity is built. For nature conservation this means: protecting biodiversity must not be limited to visible species and landscapes. It must also include the hidden systems in the soil. Anyone who wants to preserve insects, birds, and plants must also protect life below the surface. Biodiversity does not end at the soil surface.

When science and politics drift apart

These findings are especially explosive against the backdrop of current political developments. The EU is currently debating allowing pesticides to be approved partly without time limits and reducing regular re-evaluations. These plans contradict a growing number of scientific studies. A recently published study from France showed that pesticide-related effects are associated with population declines in around 84% of the bird species studied. Another study published in 2025 documented negative impacts of pesticides on more than 800 species, including vertebrates, invertebrates, microorganisms, and plants.

Against this backdrop, unlimited approvals and delayed re-evaluations do not look like sensible red tape reduction, but rather a step backward in environmental and health protection. Many problematic active substances were recognized as harmful only after years or decades, often only after irreversible damage had occurred.

The current Nature study underscores how important regular and comprehensive reviews are. It shows that even approved and legally used products can have long-term ecological side effects that are barely captured in traditional approval procedures. If these procedures are weakened further, the risk grows that environmental impacts will be systematically underestimated or recognized too late.

At the same time, the EU officially aims to protect biodiversity, make soils more resilient, and adapt agriculture to climate change. Unlimited approvals would, however, reinforce precisely the dependence on chemical inputs that undermines these goals.

The new study is therefore not only a scientific finding but also a political warning: an agriculture that gradually destroys its biological foundations jeopardizes its own long-term future.

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Source

• Köninger, J., Labouyrie, M., Ballabio, C., et al. (2026). Pesticide residues alter taxonomic and functional biodiversity in soils. Nature. https://doi.org/10.1038/s41586-025-09991-z