A soil test that started with one package of white cotton briefs in southwestern Ontario has picked up an international science prize. On 3 September 2026, at the first Ig Nobel ceremony held outside the United States, in Zurich, a Swiss team received the soil science award for a study in which about 1,000 volunteers buried more than 2,000 pairs of cotton underpants. The Ig Nobels honour research that "makes people laugh, then think", and Farmtario reports that the idea behind this one began in Chatham-Kent.
Where it started
In 2015, Claire Coombs, then a technician with Ontario's agriculture ministry, and soil management specialist Anne Verhallen heard at a Midwest cover crop conference that buried cotton makes a simple indicator of soil life. Dresden-area farmer Woody Van Arkel came up with the name "Soil Your Undies". Coombs buried a pair in a no-till field on Blake Vince's farm near Merlin, which had decades of no-till and heavy cover cropping, and another across the road in a conventionally tilled field. Two months later the no-till pair was mostly gone. The tilled pair was nearly whole.
The demonstration spread through field days, the Innovative Farmers Association of Ontario, farm media and social media. Coombs is clear that it is "not a strong scientific thing, but it's a good demonstration".
What the Swiss study added
The Swiss project, called Proof by Underpants and led by Marcel van der Heijden of the University of Zurich and Franz Bender of Agroscope, turned the demonstration into data. In 2021, volunteers buried standard cotton underwear plus about 12,000 tea bags at roughly 1,000 sites in gardens, fields, meadows and lawns, then dug them up after two months and sent them in with soil samples. The results, published in Plants, People, Planet in August 2026, found that land use was the strongest predictor of how fast the cotton broke down, ahead of soil chemistry. Private gardens, which had the most organic carbon and nutrients, showed the most biological activity. Lawns showed the least. Cropland and grassland fell in between. The authors propose an "Underpants Index" as an easy first check of soil health.
Try it on your own farm
The method costs a few dollars. Wash a pair of plain 100% cotton briefs (the elastic waistband survives and makes them easy to find), bury them a few inches deep with the waistband showing, and dig them up after about two months. Bury a second pair in a contrasting field or under a different practice at the same time so you are comparing like with like. More missing cotton means more active soil life. The researchers suggest keeping soil covered, adding compost, diversifying rotations and limiting mineral fertiliser and pesticides to build that activity.
It is not a lab test, but it is a cheap, honest way to see whether cover crops and reduced tillage are changing your soil.
References:
- Soil health assessment using buried cotton underpants with the help of 1000 citizen scientists, Plants, People, Planet (2026)
- Buried Underwear Shows Land Use Is Key to Soil Health, University of Zurich (2026)
- Award-Winning Underpants, University of Zurich (2026)
- Proof by Underpants, Agroscope
- How active is your soil? Try the underwear test!, ONfruit (2015)
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