Abstract: In order to investigate the response of greenhouse gas (CO₂,CH₄ and N₂O) fluxes of grassland to different mowing-intensity treatments and optimize the way and intensity of utilization of grassland,a different mowing-intensity experiment was conducted in the leymus secalinus communities of northwestern Shanxi province. We used the static chamber/gas chromatography (GC) technique to investigate the effects of different mowing-intensity treatment (no-mowing,light-mowing,moderate-mowing and heavy-mowing treatment) on three greenhouse gas (CO₂,CH₄ and N₂O) fluxes and the relationship between greenhouse gas fluxes and major environmental factors quantitatively. The results of the growing season and non-growing season in 2017 and 2018 showed that the grassland with different mowing-intensity treatment showed the source of CO₂ and N₂O and the sink of CH₄;mowing significantly affected CH₄ and N₂O fluxes in the growing season of 2018 (P<0.05);the fluxes of the three greenhouse gases were significantly correlated with soil temperature (P<0.05) and the fluxes of CO₂ were significantly linearly correlated with volumetric soil water content and N₂O fluxes (P<0.05). The study provides a certain reference and theoretical basis for adopting reasonable mowing-intensity treatment of grassland.

Key words: Northwestern Shanxi province, Leymus secalinus communities, Mowing intensity, Greenhouse gas fluxes, Major environmental factors

摘要： 为探讨草地温室气体通量对不同刈割强度的响应情况、优化草地利用方式及强度，本研究通过在晋西北赖草（Leymus secalinus）草地构建不同强度的刈割试验，采用静态箱/气相色谱法定量研究了不刈割、轻度刈割、中度刈割和重度刈割对3种温室气体（CO₂，CH₄和N₂O）通量的影响及温室气体通量与主要环境因子的关系。2017年和2018年生长季及非生长季观测结果表明，不同刈割强度下的草地均表现为CO₂和N₂O的源、CH₄的汇；刈割于2018年生长季显著影响CH₄和N₂O通量（P<0.05）；3种温室气体通量与土壤温度呈显著指数相关（P<0.05），CO₂通量与土壤体积含水量、N₂O通量呈显著线性相关（P<0.05）。本研究为采用合理的草地刈割强度提供一定的参考和理论依据。

关键词: 晋西北地区, 赖草草地, 刈割强度, 温室气体通量, 主要环境因子