Why did scientists ask 1,000 people to bury their underwear in Switzerland?

Scientists in Switzerland asked 1,000 volunteers to bury cotton underwear to measure soil activity. More than 2,000 pairs were buried for two months, with faster decomposition indicating greater biological activity underground. Findings published showed decomposition was fastest in private gardens and slowest in lawns. Researchers proposed an "Underpants Index" to help explain soil processes.