Impact of rice-fish/shrimp co-culture on the N2O emission and NH3 volatilization in intensive aquaculture ponds.

How to reduce the gaseous nitrogen (N) pollution (N2O and NH3) of intensive aquaculture ponds to atmosphere has gained increasing attention for the sustainable development of aquaculture. In this study, we constructed a new rice-fish/shrimp co-culture system in aquaculture ponds by using a specially developed high-stalk rice variety, and performed a 2-year field experiment to investigate the effect of this system on the N2O and NH3 emissions from yellow catfish and freshwater shrimp ponds. The results showed that the mean emission factors of N2O and NH3 to the total N input in feed was 0.18% and 0.89% for catfish monoculture pond, and 2.46% and 13.45% for shrimp monoculture pond, respectively. Rice-fish/shrimp co-culture not only reduced the N2O and NH3 emission from rice platform of catfish and shrimp ponds, but also mitigated the N2O and NH3 emission from the ditch without rice planted. The total amount of N2O and NH3 were respectively mitigated by 85.6% and 26.0% for catfish pond, and by 108.3% and 22.6% for shrimp pond, as compared with that of monoculture ponds. Co-culture system was more effective on the mitigation of gaseous N loss in the catfish than shrimp ponds.