Acidification may strip Indian soils of 3.3 billion tonnes of essential carbon, affecting crop growth, sequestration: Study

Acidification may strip Indian soils of 3.3 billion tonnes of essential carbon, affecting crop growth, sequestration: Study

Subject: Science and tech

Section: Health

Context:

• A recent study has raised concerns about the significant loss of soil inorganic carbon (SIC) due to soil acidification in India, where over 30% of cultivable land carries acidic soil.

Details:

• This acidification, primarily driven by industrial activities and intensive farming, is projected to lead to a loss of 3.3 billion tonnes of SIC from the top 0.3 meters of soil over the next 30 years.
• SIC, which includes mineral forms like calcium carbonate, is crucial for regulating nutrient levels, fostering plant growth, and carbon storage.
• The study highlights that acidic soils, particularly prevalent in India’s humid southwestern, northeastern, and Himalayan regions, reduce the availability of nutrients to plants and increase susceptibility to stress factors.
• With a focus mainly on soil organic carbon (SOC) in past research, SIC has been relatively neglected, though it is a substantial carbon pool.
• Soils store more than thrice the quantity of carbon in vegetation or double the quantity of carbon in the atmosphere.
• The findings underscore the global importance of SIC, with estimates that global soils store approximately 2,305 billion tonnes of carbon as SIC.
• India, along with China, faces significant future risks due to ongoing soil acidification, exacerbated by nitrogen fertilization and deposition.
• The potential relocation of lost SIC to deeper soil layers or its release into the atmosphere or water bodies remains a concern.
• The study calls for more comprehensive assessments of soil pH and strategies to mitigate the negative impacts of agricultural practices on SIC, emphasizing the role of SIC in climate change mitigation and carbon sequestration efforts.

Soil Organic Carbon (SIC):

• Soil organic carbon (SOC) comes from plants, animals, microbes, leaves and wood, mostly found in the first metre or so.
• Soil organic carbon is a measurable component of soil organic matter. Organic matter makes up just 2–10% of most soil’s mass and has an important role in the physical, chemical and biological function of agricultural soils.
• Organic matter contributes to nutrient retention and turnover, soil structure, moisture retention and availability, degradation of pollutants, and carbon sequestration.
• Soil organic matter is composed mainly of carbon, hydrogen and oxygen, and has small amounts of other elements, such as nitrogen, phosphorous, sulfur, potassium, calcium and magnesium contained in organic residues.
• It is divided into ‘living’ and ‘dead’ components and can range from very recent inputs, such as stubble, to largely decayed materials that might be many hundreds of years old. About 10% of below-ground SOM, such as roots, fauna and microorganisms, is ‘living’.

Source: DTE