A new study shows the base rate of organic carbon decomposition in soil across the United States can differ by as much as ten times. Soil holds more carbon than the atmosphere and plants combined, so the speed of decay matters for climate projections.
Researchers collected soil samples from 20 sites in the National Ecological Observatory Network (NEON). They incubated the samples in the laboratory for 18 months and measured carbon dioxide emissions and 26 soil properties to estimate decay rate and carbon use efficiency. The study appears in One Earth.
Machine learning helped find important factors such as soil type, pH and nitrogen. The analysis also showed links to fungal abundance and certain forms of iron and aluminum, which help stabilize organic carbon for many years.
Difficult words
- decomposition — the process of breaking down materials
- incubate — to keep samples under controlled conditionsincubated
- stabilize — to make something remain in place longer
- abundance — a large amount of something present
- emission — gases that come out from a sourceemissions
Tip: hover, focus or tap highlighted words in the article to see quick definitions while you read or listen.
Discussion questions
- Are you surprised that soil holds more carbon than the atmosphere and plants? Why or why not?
- Which soil factor from the article (soil type, pH, nitrogen) seems most interesting to you?
- How can knowing the speed of decay help with climate projections?
