An aerial drone photo taken on April 9, 2024 shows a terraced field in Miyi County, southwest China's Sichuan Province. [Photo/Xinhua]
Soil carbon usually refers only to the organic matter component of soils, known as soil organic carbon (SOC). However, soil carbon also has an inorganic component, known as soil inorganic carbon (SIC).
Solid SIC, often calcium carbonate, tends to accumulate more in arid regions with infertile soils, which has led many to believe it is not important.
In a study recently published in the journal Science, a team of researchers led by Huang Yuanyuan from the Institute of Geographic Sciences and Natural Resources Research of the Chinese Academy of Sciences (CAS) and Zhang Ganlin from the Institute of Soil Science of the CAS, have quantified the global store of SIC, challenging the long-held view.
The researchers found a whopping 2,305 billion tonnes of carbon stored as SIC in the top two meters of soil worldwide, which is more than five times the carbon found in all of the world's vegetation. This hidden pool of soil carbon could be key to understanding how carbon moves around the globe.
This huge carbon pool is vulnerable to changes in the environment, especially soil acidification. Acids dissolve calcium carbonate and remove it either as carbon dioxide gas or directly into the water, Huang said.
"Many regions in countries like China and India are experiencing soil acidification due to industrial activities and intense farming. Without remedial actions and better soil practices, the world is likely to face a disturbance of SIC in the next 30 years," she added.
Disturbances to SIC accumulated over Earth's history have a profound impact on soil health. This disruption compromises the soil's ability to neutralize acidity, regulate nutrient levels, foster plant growth, and stabilize organic carbon.
Essentially, SIC plays a critical dual role in storing carbon and supporting ecosystem functions that depend on it.
The researchers revealed that approximately 1.13 billion tonnes of inorganic carbon are lost from soils to inland waters each year. This loss has profound but often overlooked implications for carbon transport among land, atmosphere, freshwater and ocean.
While society has recognized the importance of soils as a fundamental part of nature-based solutions to combat climate change, much of the focus has been on SOC. The study indicates that SIC deserves equal attention.
The study underscores the urgency of incorporating inorganic carbon into climate change mitigation strategies as an additional lever for maintaining and enhancing carbon sequestration.
International programs such as the "4 per 1000" Initiative, which aims to increase SOC by 0.4 percent annually, should also consider the critical role of inorganic carbon in achieving sustainable soil management and climate mitigation goals.
By broadening the understanding of soil carbon dynamics to include both organic and inorganic carbon, the researchers hope to develop more effective strategies for maintaining soil health, enhancing ecosystem services, and mitigating climate change.
Husband of Florida woman missing in Spain is charged with her disappearance
Ministers told to redraw green plans after High Court rules UK's current net zero strategy unlawful
Rockies lead from start to finish for the first time this year in 3
Former New York Giants player Aaron Thomas, who caught 35 touchdown passes, dies at 86
Justin Steele returns from hamstring injury as Cubs take on Padres
AP PHOTOS: South and Southeast Asian countries cope with a weekslong heat wave
A tornado hit an Oklahoma newsroom built in the 1920s. The damage isn't stopping the presses
Stanton and Rizzo help Yankees rally in 9th inning for 2
Here's where Biden and Trump stand on 10 key issues
Michigan Supreme Court rules against couple in dispute over privacy and drone photos of land