Ghosts of past pesticide use could haunt organic farms for decades

Despite the increasing use of pesticides in agriculture, some farms have switched to organic practices and are avoiding their use. But it is uncertain whether chemicals applied to the ground for decades can continue to affect soil health after switching to organic management. Now, ACS researchers write ‘ Environmental Science and Technology Pesticide residues have been identified in 100 Swiss farms, including all the studied organic fields, with an abundance of soil microbes being adversely affected by their occurrence.

Fungicides, herbicides and pesticides protect crops by repelling or destroying organisms that are harmful to plants. In contrast, management strategies for organic farming avoid adding synthetic materials and instead rely on a supposedly healthy soil ecosystem. However, some organic farms operate on land that has been treated with pesticides in the past. However, it is unclear whether the pesticides have a long-term presence in organically managed fields and what implications for soil life, specifically beneficial soil microbes and fungi, will have after years of use. Therefore, Judith Rideau, Thomas Bocelli, Florian Walder, Marcel van der Heiden and their colleagues wanted to examine the levels of pesticides and their impact on soil health on farms managed using traditional versus organic practices, as well as on farms that had been converted to organic methods.

The researchers measured the topsoil properties and the concentrations of 46 regularly used pesticides and their degradation products in samples from 100 fields managed with either conventional or organic practices. Surprisingly, researchers have found pesticide residues at all sites, including organic farms that were converted more than 20 years ago. Multiple herbicides and one fungicide remained in the topsoil after switching to organic practices; Although the total number of synthetic chemicals and their concentrations decreased significantly the longer the fields in organic management. According to the researchers, some pesticides can contaminate organic fields by traveling through air, water, or soil from nearby traditional fields. In addition, the team observed decreased microbial abundance and decreased levels of the beneficial microbe when fields had higher numbers of pesticides in the fields, indicating that the presence of these substances could reduce soil health. The researchers say future work should examine the synergistic effects of pesticide residues and other environmental pressures on soil health.


The authors acknowledge funding from Agroscope, the Swiss Federal Office for the Environment, the Swiss National Science Foundation and the National Research Program “Sustainable use of soil as a resource”.

The paper is freely available as an ACS AuthorChoice article here.

For more recent research news, register for our next meeting, ACS Spring 2021. Journalists and media personnel are encouraged to apply for free press registration by emailing us. [email protected]

The American Chemical Society (ACS) is a nonprofit organization registered by the US Congress. ACS’s mission is to develop the broader chemistry project and its practitioners for the benefit of the Earth and its people. The Society is a global leader in providing access to chemistry-related information and research through its multiple research solutions, peer-reviewed journals, scientific conferences, e-books, and weekly newsletters. Chemistry and Engineering News. Journals of the American Academy of Sciences are among the most cited, most trusted, and most read in the scientific literature however, ACS itself does not conduct chemical research. As a specialist in scientific information solutions (including SciFinder® And stn®), Its CAS division supports global research, discovery and innovation. The ACS headquarters are located in Washington, DC and Columbus, Ohio.

To automatically receive newsletters from the American Chemical Society, call [email protected]

Follow us: Twitter | The social networking site Facebook

Related Articles

Leave a Reply

Your email address will not be published. Required fields are marked *

Back to top button