Soil organic carbon pool in Indian forests

Abstract

A database of published measurements (with depth) of soil organic carbon (C) containing information on location, soil type, texture, measured/estimated bulk density and forest type in Indian forests was prepared. It was used for estimating soil organic C densities for various forest types for two-depth classes (0–50 and 0–100 cm). The mean soil organic C density estimates for top 50 cm based on 175 observations ranged from 37.5 t/ha in tropical dry deciduous forest to 92.1 t/ha in littoral and swamp forest. The mean soil organic C density estimates based on 136 observations ranged from 70 t/ha in tropical dry deciduous forest to 162 t/ha in montane temperate forest for top 1 m soil depth. The estimated soil organic C densities were combined with remote sensing based recent forest area inventory (64.20 Mha) by Forest Survey of India [The State of Forest Report, Forest Survey of India (FSI), Ministry of Environment and Forest, Govt. of India, Dehradun, 80 pp.] to arrive at estimates of soil organic C pool by major forest types of India. The total soil organic C pools in Indian forests have been estimated as 4.13 PgC 1 PgC=10 15 gC . 1 in top 50 cm and 6.81 PgC in top 1 m soil depth. These estimates may be taken valid for 1980–1982 period on which the remote sensing based forest area assessment was made by FSI. The historic loss in forest soil organic C pool (1880–1981) in top 1 m soil depth has been estimated as 4.13 PgC. The estimated soil organic C densities by forest types can form input in models for estimating net C release from forests by deforestation as well as in estimation of historic loss in soil organic C pool in Indian forests.