Methane formation in soil–plant systems treating wastewater as influenced by microbial populations

Abstract

The present study evaluated the effect of plant species on methane (CH4) emission and microbial populations in three types of soil–plant systems. Results showed large variation of CH4 flux rate ranging from 1.35 to 212.61 mg CH4 m−2 h−1. Emission peak of CH4 occurred in July. No significant difference was found in the non-vegetation system spanning 2 years. Compared with non-vegetation, vegetation systems had much higher flux of CH4, and obvious seasonal variation was observed. The polyculture system planted with Zizania latifolia (Z. latifolia) and Phragmites australis (P. australis) released higher CH4 fluxes than the mono system (P. australis), reflecting that Z. latifolia growth could simulate CH4 emission. The fluorescence in situ hybridization (FISH) results support the characteristics of CH4 fluxes. Much higher methanotrophs amount and lower methanogens amount from the mono system than those from the polyculture system was observed indicating that Z. latifolia growth may limit the oxygen transportation resulting in higher CH4 emission. The polyculture system has the highest potential of CH4 emission.