The Swiss project called Proof by Underpants went into the ground in 2021, and its authors say their results suggest the test reflects soil fertility more strongly than soil health in the broader ecological sense, with the gardens that rotted the most cloth also carrying phosphorus far above the level Swiss guidelines call optimal.
About a thousand people across Switzerland buried cotton underpants at sites of their own choosing for two months, and the pairs pulled out of private gardens had lost around 58 percent of their fabric against around 40 percent under lawns — how the land was used predicted the rotting better than any single soil measurement the researchers took
Science Blog Editorial Team