Living microbial biomass is a highly active and heterogeneous pool , which is controlled by nutrient (e.g,. N and P) availability and directly affects the C turnover rates. N, P, K, Ca, and S are limiting elements for SOM mineralization in terrestrial ecosystem, especially in paddy soil. The CO2 emission rates decreased over the first 17 days and then remained nearly constant until the end (day 60) for both low and high nutrient input levels.