Land-use change affects carbon storage and lability in tropical soil of India

Soils are storehouse of organic carbon that is amenable to different degrees of degradation. But, information on the impact of land use change on carbon storage and lability in tropical soil is scarce. The present investigation aimed to study the carbon fractionation of tropical soils concerning their accumulation based on differential chemical oxidation involving potassium dichromate and sulphuric acid. The work was carried out in a tropical forest and pasture lands (located at a mean distance of 60 m from each other) in India. The readily oxidizable carbon (active carbon pool) dominated both the studied land uses (forest and pasture) more than the less oxidizable fraction (passive carbon pool). The carbon pool index and the carbon management index computed from the results of the two carbon pools favored the forest land for long-term carbon sequestration and were significantly correlated with the active carbon pool (p < 0.05). The results further showed a significant variation in the cumulative soil organic carbon stock of the forest (248.92 t/ha) and the pasture (184.21 t/ha) land (p < 0.05). Soil depth did not show any impact on the carbon fraction distribution. It can, thus be, concluded that land use change alters the stability and lability of organic carbon and its storage in tropical soils. Therefore, regular evaluation of carbon pools and subsequent carbon management can enhance the prospects of the long-term stay of carbon in the soil.