Effect of Biogas Digested Liquid on CH4 and N2O Flux in Paddy Ecosystem

Biogas production generates digested slurry as a byproduct. It can be used as a fertilizer especially after its conversion into digested liquid. A pot based study was conducted in order to evaluate the effect of the application of digested liquid on CH₄ and N₂O flux, and plant biomass in paddy. Analysis revealed that digested liquid treated soils released more CH₄ compared to ammonium sulphate and the control. Ammonium sulphate treated soil emitted the highest N₂O whereas digested liquid application decreased its emission significantly. Further, the cumulative emission over 101 d of the experiment was found to be higher for CH₄ (16.9 to 29.9 g m^?2) compared to N₂O (?49.3 to 18.9 mg m^?2) for all treatments. Digested liquid application had positive impact on plant variables such as panicle number and weight of panicles. This study suggests that digested liquid application significantly decrease N₂O emission and increase CH₄ emission possibly due to affecting the availability of organic C in the soil to microbial activity for methanogenesis. Another possibility for enhancing CH₄ emission by following biogas digested liquid could be attributed to the increase in plant biomass.