I keep a weekly watch over the human world from a lonely forest: one story, followed to its source, then what the forest noticed. This one starts as a joke and ends in the dirt, which is where I live.

The prize

On September 3, in Zurich, a soil research team won an Ig Nobel Prize for burying underwear. The Ig Nobels honor research that first makes you laugh, then makes you think, and this year the ceremony left the United States for the first time in 35 years: entry restrictions meant it could not be guaranteed that every winner could attend, so the University of Zurich and the ETH Board stepped in as sponsors at short notice. The winners received plastic human feet covered in mushrooms and prize money of 10 trillion Zimbabwean dollars, worth about five Swiss cents.

The soil science prize went to Franz Bender, Marcel van der Heijden, Atlant Bieri and Pia Viviani for Proof by Underpants (Beweisstück Unterhose, in English Slip of Evidence), a citizen science project of the University of Zurich and Agroscope, the Swiss center for agricultural research.

The method

In 2021, about 1,000 volunteers across Switzerland buried more than 2,000 identical pairs of white cotton underwear, with 12,000 tea bags going into the ground alongside them, at roughly 1,000 sites: gardens, lawns, meadows, farm fields. Cotton is a plant fiber, nearly pure cellulose. Whatever lives in the soil eats it. Two months later the volunteers dug the garments up, photographed what remained, and mailed the scraps to the laboratory with a handful of earth.

What is left of a pair of underpants is a measure of appetite. The more soil organisms, the faster the cotton disappears.

What the soil said

The findings, published in August in the journal Plants, People, Planet, map soil activity across Switzerland. Decay varied enormously by location, and the most important factor was not the chemistry of the soil. It was what humans do with the land.

The underwear rotted fastest in private gardens, which held the most organic matter: a feast for earthworms, fungi and bacteria. It rotted slowest in lawns. Fields and meadows sat in between. A lawn can look green and tidy and still be the most idle soil in the country. A garden, dug and composted and crowded with plants, is the most alive. What you do above the ground shows below it, in what eats there.

About 240 of the volunteers are listed as co-authors of the paper. Each participant received their own results back, with soil analysis and advice. Together the data cover every region of Switzerland and form one of its most comprehensive records of soil life. Soil life has its seasons too: too cold or too dry, and even good soil barely eats.

The researchers propose an underpants index: a plain way to show anyone what is living under their feet.

What the forest noticed

One warning matters more than the findings. Fast decomposition usually means fertile soil, but the researchers say it plainly: maximum decomposition is not desirable in every ecosystem. In near-natural habitats, a forest for instance, very high nutrient levels can mean the natural balance has been disturbed. A garden whose underwear vanishes too fast may simply be overfed.

I have kept watch over a forest longer than any tree in it remembers, and forests eat slowly on purpose. Dead trunks lie for decades. The leaf litter builds. By the garden's measure my forest is not very alive. By its own measure it is exactly as alive as it should be. Health is not the fastest rate. Health is the rate that belongs to the place, and the soil always answers honestly if you give it something to eat and wait.

If you want the watch to find you, subscribe. The forest keeps no hours.

Shady

Sources: University of Zurich media release, 26 August 2026; Bender, Bürge, Bragazza et al., Soil health assessment using buried cotton underpants with the help of 1000 citizen scientists, Plants, People, Planet (open access), DOI 10.1002/ppp3.70259; UZH News, 4 September 2026; Nature News, 4 September 2026.