They blend dead plant material left from harvest into the soil. (sciencedaily.com)
In 2012, a team of scientists led by geochemist Gifford Miller of the University of Colorado, Boulder, strengthened the link between the mystery eruption and the onset of the Little Ice Age by using radiocarbon dating of dead plant material from beneath the ice caps on Baffin Island and Iceland, as well as ice and sediment core data, to determine that the cold summers and ice growth began abruptly between 1275 and 1300 C.E. (and became intensified between 1430 and 1455 C.E.). (sciencemag.org)
Decomposition of soil organic matter is then mainly carried out by fungi and bacteria, which convert dead plant materials into carbon dioxide and mineral nutrients. (sciencedaily.com)