u/Track_Shovel posted this study on !soilscience@slrpnk.net:

Soil health assessment using buried cotton underpants with the help of 1000 citizen scientists

If you needed another reason to ditch your lawn, here it is

From the study:

Private gardens, the land-use type with the highest levels of soil organic carbon [SOC] and nutrients, exhibited the greatest biological activity, whereas lawns showed the lowest, with croplands and grasslands falling in between.

[…]

The project was launched under the title “Proof by underpants,” and the extent of decomposition was termed the “Underpants Index” (UI)

Why underpants?

Decomposition can be assessed using a wide range of organic materials. Cotton strips have previously been applied (Harrison et al., 1988; Nachimuthu et al., 2007), while the Tea Bag Index (TBI) makes use of commercially available teabags with standardized composition for the same purpose (Keuskamp et al., 2013). Due to the wide availability of the material, the TBI has been employed in a citizen science approach to gather global decomposition data (Sarneel et al., 2024). However, despite being relatively easy to apply and interpret, the method requires careful handling and specific tools, such as a fine scale balance. Moreover, it lacks visual appeal and may struggle to attract broader public attention for soil-related topics. A more playful approach that has occasionally been used to illustrate soil decomposition, though without scientific rigor, is the burial of cotton underpants (Figure 1). Beyond providing a sensory experience of decomposition and soil biological activity, this approach has potential to engage society and gather quantitative data through citizen science

Effect of land use:

[…] lawns showed the lowest decomposition, averaging around 40%. Both differed significantly from arable fields that showed intermediate decomposition levels of around 51% and from permanent grasslands with decomposition levels of around 47%. Lawns also showed significantly lower decomposition than the “other land-use” category […]

Soil parameters

[…] In contrast, arable fields and lawns had the lowest SOC values averaging around 2.1%, while permanent crops and grasslands showed intermediate values. Pavail levels also varied significantly between land-use types (F5, 705 = 44.3, p < 0.001, Figure 4d). Private gardens exhibited average levels of 13.74 mg Pavail kg−1, which was significantly greater than in all other land-use types and roughly fourfold higher than what was observed in arable fields. […]

[…] Lawns, depending on their type, are often characterized by frequent mowing, low plant diversity, and regular herbicide use, all of which can negatively affect soil biological communities […]