Abstract: In order to search for an effective way to reduce the methane emission from landfill, three columns were installed, two of which were planted with Medicago sativa and Trifolium repens, respectively to simulate the biocover of landfill, and one was taken as the control, with the effects of vegetation establishment on the methane oxidation and methanotrophs community in the landfill biocover investigated. Vegetation establishment could markedly contribute to the decline of substrate moisture, increase of substrate total nitrogen, and the promotion of the diffusion of O₂ and CH₄ in the landfill biocover, being beneficial to the enhancement of methane oxidation in the substrate. At the high-speed phase and declining phase of methane oxidation, the oxidation rate of methane in the columns with vegetation establishment was significantly higher than that in the control, but there was no significant difference between the columns covered with different plants. At the low-speed phase, the methane oxidation had no significant differences between the vegetated columns and the control one, but the methane oxidation rate was significantly higher in the column planted with M. sativa than with T. repens. The microbial community derived from phospholipid fatty acid analysis (PLFA) showed that vegetation establishment promoted the growth of type I methanotrophs in the bottom layer of the columns, and, with the decline of methane oxidation rate, there was a shift from type Ⅰ methanotrophs to type Ⅱ methanotrophs at the bottom layer of the columns.

Key words: brackish water, soil enzymes, carbon flux, organic matter decomposition rate, drip irrigation.