According to a press release from the British Embassy in Beijing, a research team from Newcastle University in the UK is trying to design soils that can remove carbon from the atmosphere in a cost effective way - permanently.
"Scientists have known about the possibility of using soil as a carbon 'sink' for some time," said Professor Manning of soil science at the University, who is leading the research. "But no-one else has tried to design soils expressly for the purpose of removing and permanently locking up carbon."
Plants, crops and trees naturally absorb atmospheric carbon dioxide (CO2) during photosynthesis and then pump surplus carbon through their roots into the earth around them. With most soils, much of this carbon escapes to the atmosphere or enters groundwater.
But the team believes that in soils containing calcium-bearing silicates (natural or man-made) the carbon that oozes out of a plant's roots may react with the calcium to form the harmless mineral, calcium carbonate. The most common natural forms of calcium carbonate are chalk, limestone and marble.
The carbon then stays securely locked in the calcium carbonate that remains in the soil, close to the plant's roots, in the form of a coating on pebbles or as grains.
The scientists are investigating whether this process occurs. If it does, then it would encourage the growth of more plants, crops and the like in places where calcium-rich soils already exist.
It would also open prospects for tailor-made soils (with added calcium silicates or specific plants) that optimize carbon-capture. Such soils could play a valuable role in carbon abatement all over the globe.
The team members will first try to detect calcium carbonate in natural soils that have developed on top of calcium-rich rocks or been exposed to concrete dust (that contains man-made calcium silicates).
They will then study artificial soils made at the university from a mixture of compost and calcium-rich rock. Finally, they will grow plants in soils made to contain a high level of calcium silicates and then monitor the accumulation of calcium carbonate there.
"Once we have confirmed the feasibility of this carbon sequestration method, we can develop a computer model that predicts how much calcium carbonate will form in specific types of soil, and how quickly.
"That will help us to engineer soils with optimum qualities from a carbon abatement perspective. A key benefit is that combating climate change in this way promises to be cheap compared with other processes," he added.
A significant scope could exist to incorporate calcium-rich, carbon-locking soils in land restoration, land remediation and other development projects. Growing bio-energy crops on these soils could be one attractive option.
"The process we are exploring might be able to contribute around 5-10 percent of the UK's carbon reduction targets in the future," said Professor Manning. "We could potentially see applications in 2-3 years, including a number of 'quick wins' in the land restoration sector."
By People's Daily Online
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