Overview
- Researchers from Agroscope and the University of Zurich coordinated a two-month citizen-science effort that invited about 1,000 volunteers to bury more than 2,000 standardized cotton underwear items and roughly 12,000 tea bags at around 1,000 Swiss sites.
- The study, which was reported on Tuesday, found cotton in private gardens lost about 58% of its mass on average after two months compared with roughly 40% in lawns, showing clear decomposition differences by land use.
- Laboratory tests showed garden soils had a mean available phosphorus of 13.74 mg/kg, far above Swiss guideline ranges of 1.6–4.3 mg/kg, indicating widespread over-fertilization and a real risk of nutrient leaching to groundwater.
- The team used cotton as a simple cellulose proxy for microbial activity and deployed tea bags as a complementary measure, arguing the resulting 'underwear index' can help communicate soil fertility and stewardship to the public.
- Authors caution that faster decomposition signals high nutrient availability rather than ecological health, so the same conditions that boost garden productivity can damage meadows and forests by favoring dominant species and reducing biodiversity.