A detailed ICAR soil organic carbon study has revealed that the unscientific use of fertilisers and climate change are degrading organic carbon in India’s arable land. The six-year-long research, coordinated by the Indian Institute of Soil Science (IISS), Bhopal, used 254,236 soil samples from 620 districts across 29 States. The findings were published in the international journal Land Degradation & Development.
According to Arvind K. Shukla, the study’s coordinator, soil organic carbon plays a vital role in maintaining the chemical, physical, and biological health of soil. He noted that organic carbon is closely linked with micronutrient availability. “If organic carbon is low, micronutrient deficiency is high. When organic carbon is higher, the deficiency is lower,” he said.
The ICAR soil organic carbon study found that elevation, temperature, and rainfall strongly influence soil carbon content. Soils in high-altitude regions contain more organic carbon, while hotter regions such as Rajasthan and Telangana show lower levels. The study confirmed that organic soil carbon is negatively correlated with temperature.
The research also developed an agro-ecological map covering 20 regions to evaluate how cropping systems and fertiliser use affect organic carbon. Rice and pulse-based systems showed higher carbon content than wheat and coarse-grain systems, largely due to greater microbial activity in irrigated fields.
Scientists warned that imbalanced fertiliser use, especially the excessive application of urea and phosphorus, has reduced organic carbon in parts of Punjab, Haryana, and Western Uttar Pradesh. In contrast, Bihar, where farmers use fertilisers more evenly, showed better soil health.
Climate change further threatens soil carbon stability. Rising temperatures could accelerate carbon loss, reducing soil fertility and increasing greenhouse gas emissions.
The study urged policymakers to promote carbon sequestration, support balanced fertiliser application, and reward farmers through carbon credits. Increasing crop cover and plantations was also recommended to restore soil health and mitigate the impact of climate change.
Sources: The Hindu