Forest Soil Organic Carbon Pool: an Estimate and Review of Indian Studies

The Indian forest soil organic C densities for two-depth classes (top 50 cm and 1 m) were estimated using a database of published measurements with depth of soil organic carbon (SOC) containing information on location, soil type, texture, measured/estimated bulk density and forest type. 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 tha^-1 in littoral and swamp forest. The mean soil organic C density estimates for top 1 m depth based on 136 observations ranged from 70 tha^-1 in tropical dry deciduous forest to 162 tha^-1 in montanc temperate forest. The estimated soil organic C densities were combined with remote sensing (RS)-based forcst area inventory to arrive at cstimates of soil organic C pool of major forest types of India. The total soil organic C pools in Indian forests were estimated as 4.1 and 6.8 PgC (PgC = 10¹⁵ gC) in top 50 cm and top 1 m-soil depths, respectively. The estimate is comparable to carlier Indian forest soil organic C pool estimates, which are in the range of 5.4-6.7 PgC (top 1m depth). A few Indian studics were also reviewed to dctermine the impact of various anthropogenic changes such as conversion of natural forests to plantations, deforestation, and shifting cultivation on forest soil organic C pools.