Abstract: By the method of static chamber, the seasonal and diurnal variations of N₂O fluxes in two fullscale municipal solid waste (MSW) landfills covered with sandy and clay soils were measured to study the effects of leachate irrigation and cover soil type on the landfill N₂O emission. The results showed that the N₂O flux in the MSW landfill covered with sandy soil was （242±576） μg N₂ON·m^-2·h^-1 in summer, being 3.2 times (P>0.05) as high as that in spring ［(74.4±314） μg N₂O N·m^-2·h^-1］, while the N₂O flux in the MSW landfill covered with clay soil was （591±767） μg N₂ON·m^-2·h^-1 in summer, being 2.2 times (P<0.05) as high as that in spring ［(269±335） μg N₂ON·m^-2·h^-1］. Leachate irrigation promoted the N₂O emission from the soil cover of the landfill covered with sandy soil, and the N₂O flux in the landfill was 1 time higher than that of the control (P>0.05). Under leachate irrigation, the average N₂O flux in spring and summer in the landfill covered with sand soil was （211±460） μg N₂ON·m^-2·h^-1, being only 1/2 of that ［(430±605） μg N₂ON·m^-2·h^-1］ in the landfill covered with clay soil without leachate irrigation (P>0.05). Therefore, no matter leachate irrigation was conducted or not, the N₂O emission from MSW landfill could be inimized by covering with infertile sandy soil.

Key words: chestnut (Castanea mollissima), biological organic fertilizer, soil microbial community, carbon source utilization rate (AWCD).