Switzerland soil study uses buried cotton underwear to map biological activity

Researchers from the University of Zurich and Agroscope have published results from a unique citizen science project called ‘Beweisstück Unterhose’ (Proof by Underpants) to map soil health across Switzerland.

In the study, approximately 1,000 volunteers buried over 2,000 pairs of standard 100% cotton underwear and 12,000 tea bags at roughly 1,000 locations. After two months, the items were retrieved to measure the rate of decomposition. Because cotton is made of cellulose, its breakdown serves as a direct indicator of biological activity from bacteria, fungi, and earthworms.

The findings revealed that private gardens and orchards showed the highest levels of soil activity and organic matter. In contrast, manicured lawns and conventional agricultural lands showed lower decomposition rates. The study highlights how land management practices, such as organic farming and no-till agriculture, significantly influence soil vitality and ecosystem services like nutrient cycling and carbon storage.