The short version
- One thousand Swiss citizens participated in an experiment burying organic cotton underpants to measure local soil decomposition rates.
- The study found that land use type was the primary determinant of how quickly the fabric broke down, with private gardens showing the highest activity.
- Researchers concluded that this method provides data comparable to traditional teabag indices while being more accessible for public engagement.
A novel citizen science initiative conducted across Switzerland has utilized buried organic cotton underpants as a tool to assess soil health on a national scale. The project, which involved one thousand volunteers, aimed to map decomposition rates and biological activity in various environments. Results from the experiment, recently published in the journal Plants People Planet, indicate that land management practices are the most significant factor influencing how quickly organic matter breaks down in the ground.
The study was designed to address a gap in large-scale national decomposition research. While soil health is vital for agriculture and global ecosystems, it has been declining worldwide. Decomposition rates of complex organic materials serve as a key indicator of soil quality, reflecting the ability of the earth to cycle nutrients and support life. Previous methods, such as the teabag index, require precise equipment and careful handling that can be barriers to widespread public participation.
To create a more engaging and accessible approach, researchers led by Marcel van der Heijden at the University of Zurich developed what they termed the underpants index. Volunteers received kits containing two pairs of organic cotton men’s underwear, twelve teabags for comparison, and soil sampling bags. Participants were instructed to select a site, collect a soil sample, and bury the items vertically with the synthetic waistband remaining visible above the surface.
The experimental protocol required participants to retrieve the first pair of underpants and associated teabags after thirty days, followed by the second set after sixty days. This timeline allowed scientists to observe decomposition progress at two distinct intervals. All materials were then mailed back to the research team for detailed analysis, enabling a comprehensive comparison between the new method and established standards.
Analysis of the returned samples revealed that land use type was the dominant variable affecting decomposition speed. Private gardens exhibited the fastest breakdown rates, correlating with higher levels of organic matter in the soil. These environments proved ideal for earthworms, fungi, and bacteria, which drive the decomposition process. In contrast, lawns showed the lowest level of biological activity among the tested sites.
Agricultural fields and meadows occupied a middle ground in terms of decomposition rates. The study also identified that environmental conditions such as temperature and moisture played crucial roles in organism activity. Extreme cold or dryness slowed down the breakdown process, while nutrient levels in the soil further influenced the speed at which the cotton fibers degraded.
The researchers found that the underpants index provided data on chemical and physical soil properties, elevation, and moisture that was equally meaningful as the traditional teabag index. However, the visual and tactile nature of the underpants made the results easier for non-experts to interpret. This accessibility makes the method particularly suitable for citizen science projects aimed at raising awareness about soil-related issues.
The project successfully engaged a large number of participants, with two hundred forty volunteers listed as co-authors on the resulting paper. By involving the public directly in data collection, the study not only gathered extensive geographic coverage but also fostered greater understanding of local soil conditions. The findings underscore the importance of biologically active soil for fertility and ecosystem services.
This approach highlights a shift toward more playful and inclusive methods in environmental science. While traditional metrics remain valuable, tools that offer direct visual feedback can bridge the gap between scientific data and public comprehension. The success of this experiment suggests that similar methods could be applied in other regions to monitor soil health and promote sustainable land management practices.
The study contributes to the growing body of evidence linking human land use decisions to ecological outcomes. As global attention turns to soil conservation, innovative monitoring techniques like this one provide practical ways to assess progress. The data collected offers a snapshot of current conditions while establishing a baseline for future comparisons in Swiss soil health.
Sources behind this briefing
Go to the original reporting
- Ars Technica↗Why did 1,000 Swiss citizens bury their underpants?
