SOIL ORGANIC CARBON (SOC) (Syllabus: GS Paper 3 – Agriculture)

Context: Recent data from the state's Agriculture Department revealed that more than half of Karnataka's agricultural land suffers from low levels of soil organic carbon (SOC)  a critical indicator of soil health and fertility.

Soil Organic Carbon (SOC)

• About: It is a measureable 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: SOM encompasses all organic components in the soil, but is challenging to measure directly, leading laboratories to focus on measuring and reporting SOC instead.
• SOC's Role in Carbon Sequestration: SOC plays a crucial role in carbon sequestration, which is a method proposed to mitigate climate change by capturing and storing atmospheric carbon dioxide in soils.
• Impact of SOC: Even small increases in SOC across large agricultural and pastoral areas can significantly reduce atmospheric carbon dioxide levels.
• Main Component of SOM: SOC, which forms the largest terrestrial carbon pool and is crucial for the planet's carbon cycle.
• Global Significance of SOC: Globally, the top 30 cm of soil contains more carbon than both the atmosphere and vegetation combined, highlighting the critical role of SOC in global carbon dynamics.
• SOC and Soil Health

o Soil Health Definition: According to the Intergovernmental Technical Panel on Soils (ITPS), soil health is defined by the soil's ability to sustain productivity, diversity, and environmental services in terrestrial ecosystems.

o Indicator of Soil Health: SOC is a vital element that enables soils to provide these essential services, making it a key indicator of soil health.