Soil organic carbon stock in agricultural land of Jorhat district of Assam

Lack of data often hamper the estimation of regional scale soil organic carbon (SOC) concentration especially in North-Eastern region of India. This study attempts to overcome the data limitations by combining District fertility database (DFD) and Soil Carbon Stock database (SCSD) for depth wise information. Representative regression models between the near-surface SOC concentration and those of deeper depths, and between SOC concentration and bulk density (BD) were developed based on the SCSD. These regression models were then applied to the DFD to derive SOC density map, resulting in an improved SOC distribution maps for the top 30 cm, 60 cm and 90 cm depths. Over all carbon stock for agricultural land of Jorhat district was found to be 8.18 Tg, 14.21 Tg and 19.78 Tg for 0–30 cm, 0–60 cm and 0–90 cm, respectively. It was found that the agricultural lands of Char area agro-ecosystem are rich in carbon density whereas, high land region is poor among all agro-ecosystems. But, in terms of carbon stock, flood prone region shows high value, even though carbon density is low, followed by flood free agro-ecosystem.