Estimation of soil organic carbon in the forest catchment of two hydroelectric reservoirs in Uttarakhand, India

ABSTRACT

Soil organic carbon (SOC) is the largest active terrestrial carbon reservoir, which behaves both as a sink and source for atmospheric carbon. The same is maximum in the forest soil of Abies pindrow (128 t ha⁻¹) and minimum in Pinus roxburghii (69 t ha⁻¹). The mitigation potential is also found to be maximum in Alpine forest soil (i.e., 1.84) in Abies pindrow and minimum in the chir (i.e., 1.00) in P. Roxburghii. This indicates that alpine forest soil can hold nearly two times more SOC than chir and hence it behaves as a CO₂ sink. The overall average content of SOC and carbon dioxide equivalent under all land use was estimated at 91.29 t ha⁻¹ and 334.11 t ha⁻¹, respectively. The objective of this study is to estimate the spatial variability of SOC stocks in the catchment of both the Tehri and Koteshwar hydroelectric reservoir using field investigations, laboratory measurements, and geostatistical methods. The study provides an estimation for the amount of carbon reaching to the reservoir through various sources, where it undergoes aerobic and anaerobic degradation, thereby releasing green house gases (GHGs) to the atmosphere. The information provided in this article will be useful for policy-makers and environmentalists for undertaking appropriate conservation plans to mitigate GHGs.

KEYWORDS:

• land use
• soil organic carbon (SOC)
• CO₂ equivalent (CO₂e)
• green house gases (GHGs)
• hydroelectric reservoirs

Acknowledgments

The authors are highly thankful to Principal Chief Conservator of Forests (PCCF), Uttarakhand, for giving permission to carry out work in the Tehri Garhwal forest division.

Funding

One of the authors (AK) acknowledges the financial support from Ministry of Human Resource Development (MHRD), Govt. of India in the form of a scholarship to carry out this research work.