A Swiss citizen-science project asked 1,000 people to bury organic cotton underpants to measure soil health across the country. The study found that land use had the strongest influence on decomposition, highlighting how soil management affects fertility, nutrient cycling and wider ecosystem services.

Volunteers buried two pairs of underpants and 12 tea bags, retrieving them after 30 and 60 days for analysis; 240 participants were credited as co-authors. Underpants decomposed fastest in private gardens, which had the most organic matter, while lawns showed the lowest soil-organism activity; fields and meadows fell between them. Temperature, moisture and nutrient levels also influenced results, and researchers said the visual “underpants index” performed as meaningfully as the established tea-bag method.