After discovering that soil erosion can actually store some carbon dioxide from the atmosphere, acting as a carbon sink, a recent discovery reveals that after some time it can also be a carbon source as its stored carbon will rise up again back to the atmosphere.
Researchers at the University of California – Davis have estimated that within 500 years, half of the carbon stored in soils will be released back to the atmosphere, and climate change may hasten this process as it increases the decomposition rate.
The researchers have calculated the amount of carbon stored in soil by utilizing radiocarbon and optical dating over a very long period of time, from 4000 BC to AD 2000, which indulged them to observe the gradual release of stored carbon back to the surrounding air.
Their study has shown that half of the carbon captured was reintroduced to the atmosphere by land conversion. Still, the carbon stored in the past 150 years by a massive agricultural land conversion has yet to be released, and thus may contribute to carbon emissions in the future, within about 500 years.
As mitigation to the future carbon releases, the researchers suggest cover cropping, which ensures no soil is left exposed to the atmosphere for carbon release, and performing agricultural methods without or with lower tilling.