Soil supports food production; stores water, carbon and nutrients; and provides habitats for more than half the world’s biodiversity, which is precipitously declining. To raise awareness about the importance of soil health and its biological activity, Swiss scientists recruited 1,000 volunteers to bury more than 2,000 pairs of cotton underwear and 12,000 tea bags across Switzerland.

After two months, the materials were dug up, photographed and sent for analysis. The findings, published in Plants, People, Planet, reported that the underwear decomposed faster in healthy, microbe-rich soils. Gardens with large amounts of organic matter showed the fastest breakdown and lawns the slowest, while farm fields and meadows were in the middle. Biological activity was affected by the soil’s nutrient levels, temperature and moisture levels. “Our results show that how soil is managed can significantly affect both soil life and soil quality,” said Marcel van der Heijden, a study leader and professor of agroecology.