Abstract: It is an arduous scientific task to understand the mechanism of land use change process affecting ecosystem biogeochemical cycles and to use models to simulate the impacts of land use change on greenhouse gas flux. Using the DNDC model, a biogeochemical process based modeling, and meteorological, soil and management data, we estimated the greenhouse gas fluxes of CH₄, CO₂, and N₂O in both new and old rice fields. Compared with the observed data, the DNDC model performed better in the old rice fields (R²>0.89, n=40, P<0.01) than in the new paddy fields (R²> 0.79, n=265, P<0.01), indicating that the model has limitations in capturing the land use change effects on greenhouse gas effluxes. The model performed better for CH₄ and CO₂ than for N₂O. Changing soil SOC concentration and pH value is not enough to fully capture the land use change effect on greenhouse gas emissions, suggesting that soil biota associated with land use change have to be considered in the future to improve the model. Using model to simulate the effects of land use change on greenhouse gas effluxes may contribute to the national greenhouse gas emission inventories and the formulation of greenhouse gas management policy.

Key words: Exopalaemon carinicauda, salinity, reproduction, growth and development.