An experiment was conducted to evaluate the active carbon under sodic soil after the
improvement through natural sources of gypsum and bio-compost. This experiment was
carried out at the Indian Agricultural Research Institute, Sub Regional Station, Pusa
(Samastipur), Bihar during the Kharif session of 2018 and 2019. The experimental site was
laidout in split plot design with four treatments of gypsum and bio-compost application in
main plots and ten rice genotypes sowed into subplots and replicated in thrice times. After the
experiment results observed that the improved soil pH, ESP, and EC significantly. The active
carbon was observed to the significantly higher in more application doses of bio-compost
than gypsum and also observed that some rice genotypes helps in improving active carbon
under-treated with bio-compost and gypsum plots i.e. CSR-36, CSR-27, CR-3884-244-8-5-6-
1-1, and CSR-30.