Grazing animals key to soil’s carbon stability: IISc study

BENGALURU: Large mammalian herbivores play a crucial role in stabilising soil carbon in the grazing ecosystem across the globe, including in the Himalayas, shows a study undertaken by researchers from Centre for Ecological Sciences and Divecha Centre for Climate Change, IISc. An experimental removal of grazing by herbivores from such ecosystems led to fluctuations in the soil carbon level, adversely affecting the global carbon cycle, researchers found.

Dead organic matter from plants and animals remain in the social for long before microbes break them down, and release carbon into the atmosphere as carbon dioxide, said Sumanta Bagchi, Associate Prof at CES. The 16-year-old study began with the assessment of the impact of grazing animals on the Himalayan ecosystems during his PhD back in 2005.

With support from the Himachal Pradesh government, local authorities, and the people of the Kibber village in Spiti region, where the study was undertaken, soil samples collected and plots created to assess chemical composition. The levels of carbon and nitrogen were also assessed in each plot.

A comparative study revealed that carbon was found to fluctuate 30-40 per cent more in the fenced plots where animals were absent, compared to the grazed plots where it remained stable each year.A key factor underlying these fluctuations was nitrogen. Depending on the soil conditions, nitrogen can either stabilise or destabilise the carbon pool.