Ig Nobel Prize: Dutch Scientist Wins for Buried Underpants

A Dutch scientist has won the 2026 Ig Nobel Prize for a citizen science experiment in which more than 1,000 volunteers buried 2,000 pairs of cotton underpants and 12,000 tea bags across Switzerland to measure soil health. Professor Marcel van der Heijden of the University of Zurich and three colleagues received the award for the playful project, officially named Proof by Underpants, which turned everyday underwear into a tool for assessing the activity of earthworms, fungi and bacteria.

What is the Ig Nobel Prize?

The Ig Nobel Prizes honor research that first makes people laugh, and then makes them think. Awarded annually since 1991, they celebrate unusual but often genuinely useful science. This year's theme was mould and fungi, and the ceremony took place in Zurich on 3 September 2026. The soil health research behind the underwear study earned the team the Soil Science prize, showing that playful methods can produce serious ecological insights.

The Buried Underpants Experiment Explained

Five years ago, Van der Heijden's team set out to understand how land use affects soil life. They initially considered burying pieces of cotton or socks, but chose underwear to attract more participants. Vlak na de aankondiging meldden duizend mensen zich aan — in English: right after the announcement, 1,000 people signed up. The final study involved more than 2,000 white cotton underpants and 12,000 tea bags buried at roughly 1,000 sites across Switzerland.

How the study worked

Volunteers followed a fixed procedure. They buried the cotton underwear and tea bags, waited two months, then dug them up, photographed the remains and sent soil samples to Van der Heijden's laboratory. The amount of decomposition revealed how active soil organisms were at each location. This approach, part of a broader citizen science projects movement, allowed researchers to gather data at a scale impossible in a single laboratory.

Key findings: land use matters most

The results, published in Plants, People, Planet, showed that land use was the strongest predictor of decomposition rates. Underpants decomposed fastest in private gardens, which had the highest organic matter, and slowest in lawns, with fields and meadows in between. Onze resultaten laten zien dat de manier waarop je de bodem verzorgt, duidelijk invloed heeft op het bodemleven en de bodemkwaliteit, Van der Heijden explained: the way you manage soil clearly influences soil life and quality. The team proposed an 'underwear index' as a simple public-awareness tool.

Why the ceremony moved from the US to Zurich

This year's Ig Nobel ceremony was the first held outside the United States in 36 years. Founder Marc Abrahams said it had become unsafe for international guests to visit the US. We cannot in good conscience ask the new winners, or the international journalists covering the event, to travel to the US this year, Abrahams stated. Swiss media linked the decision to the US immigration policy under the current administration. The plan is to alternate: Zurich every second year, with other European cities hosting in between. Antwerp is scheduled for 2027.

Impact on soil science and public awareness

The underwear study shows that healthy, active soil is crucial for fertility and ecosystem function. Fast decomposition can signal high fertility, but the researchers caution that very rapid breakdown in gardens and natural habitats may indicate nutrient oversupply, suggesting fertilizer reduction. By turning 1,000 volunteers into co-researchers, the project also boosted public understanding of soil biology. Dutch scientists have now won Ig Nobel Prizes 22 times since the awards began.

FAQ: Buried Underpants Soil Study

Why did scientists bury underpants?

They buried cotton underpants to measure how quickly soil organisms such as earthworms, fungi and bacteria decompose organic material, providing a simple indicator of soil biological activity.

How many underpants and tea bags were buried?

More than 2,000 pairs of cotton underpants and 12,000 tea bags were buried at about 1,000 sites across Switzerland by over 1,000 citizen scientists.

What did the underwear experiment find?

Land use was the key factor: decomposition was fastest in private gardens and slowest in lawns, showing that management practices strongly affect soil health.

Who won the 2026 Ig Nobel Prize for soil science?

Dutch professor Marcel van der Heijden of the University of Zurich and three colleagues won for the 'Proof by Underpants' project.

Why did the Ig Nobel ceremony move to Europe?

Organizers cited safety concerns related to US migration policy, making it unreasonable to ask winners and journalists to travel to the United States.