Terai, a Rich Hub of Soil Carbon Storage: A Case Study from Bihar

Abstract

Five typical pedons representing the Terai regions of the middle Indo–Gangetic plain of Bihar under different landforms and land uses were studied with reference to their soil carbon storage. These soils have been developed from the recent tertiary deposits of alluvial parent materials under sub humid climate. Soils are very deep, olive brown to grey in colour, silt loam to silty clay loam in texture and are frequently flooded. The soils are slightly to moderately alkaline (pH 7.5 to 8.8), medium to high in organic carbon content, low in cation exchange capacity (CEC) and high in base status. The soils are highly calcareous in nature, and the CaCO3 present in these soils are mostly geogenic rather than pedogenic. This region is characterized by marshy land at the foothills of the Himalayas. The biomass of these soils in the Terai is produced under a cool and humid climate with luxuriant vegetation growth, with an enhanced regeneration rate, which supports low rate of decomposition of organic matter. Further, the soil inorganic C pool carried by the runoff water from hills as CaCO3 also gets deposited in these Terai regions through the dissolution, transportation and reprecipitation of dissolved ions as carbonate nodules/powder. The high slopes of the northern hills, laden with eroded surface soils rich in organic, inorganic matter and other nutrients, continuously replenish the foothill soils, making it a rich hub of soil carbon storage. The Terai soils are fertile in terms of nutrient reserve and are highly productive. Farmers should protect these precious natural resources and use them judiciously, not only to increase crop production but also to maintain the ecosystem in this fragile environment.