中文关键词放牧温室气体微生物生物量半干旱草地生态系统农牧交错带 英文关键词grazinggreenhouse gasmicrobial biomasssemi-arid grassland ecosystemagro-pastoral ecotone

作者	单位	E-mail
申颜	山西农业大学动物科技学院, 太谷 030801 中国科学院植物研究所植被与环境变化国家重点实验室, 北京 100093	18234487746@163.com
孙建平	山西农业大学动物科技学院, 太谷 030801 中国科学院植物研究所植被与环境变化国家重点实验室, 北京 100093
罗玉坤	山西农业大学动物科技学院, 太谷 030801 中国科学院植物研究所植被与环境变化国家重点实验室, 北京 100093
刁华杰	山西农业大学动物科技学院, 太谷 030801 中国科学院植物研究所植被与环境变化国家重点实验室, 北京 100093
闫卫东	山西农业大学动物科技学院, 太谷 030801
王常慧	中国科学院植物研究所植被与环境变化国家重点实验室, 北京 100093	wangch@ibcas.ac.cn
董宽虎	山西农业大学动物科技学院, 太谷 030801	dongkuanhu@126.com

中文摘要 通过在北方农牧带半干旱草地生态系统（山西右玉）设置不放牧、轻度放牧、中度放牧和重度放牧4个不同强度的放牧实验，运用静态-暗箱法测定放牧第一年生长季的温室气体通量，研究不同放牧强度对该地区温室气体通量的影响.结果表明：① CO₂和N₂O在生长季表现出随着温度和水分变化的明显季节动态变化，但是与不放牧相比，第一年不同放牧强度对CO₂和N₂O排放速率没有显著影响；②放牧显著降低了土壤含水量（P<0.05），中度放牧降低了土壤微生物生物量碳（MBC，P<0.05），中度和重度放牧降低了土壤微生物生物量氮（MBN，P<0.05）；③ CO₂排放速率和土壤温度、土壤水分之间呈显著正相关关系，土壤温度、可溶性氮、微生物生物量氮以及CO₂排放速率之间呈显著正相关关系.放牧增加了温度与CO₂排放的相关性，但对N₂O排放相反.④虽然放牧降低了土壤含水量，但是没有发现不同放牧强度间CO₂和N₂O排放的差异，说明短期内不同的放牧强度尚未对土壤微生物结构与功能造成显著影响，需要继续进行长期深入地研究，揭示放牧强度对温室气体通量的影响机制. 英文摘要 Grazing is one of the most important ways for managing grassland in northern China. Different studies have focused on the effects of grazing on the structure and function of ecosystems. Grazing affects the structure and function of soil via biological and physical processes, such as animal trampling, feeding, and excretion, which further affects N₂O emissions. However, there is less research on greenhouse gases (GHGs) emissions by grazing intensities in semi-arid grassland ecosystems in northern China. In this study, four different grazing intensities were considered in the semi-arid grassland ecosystem of the typical agro-pastoral ecotone in northern China (Youyu, Shanxi). The influence of different grazing intensities on GHG fluxes was studied by measuring GHGs fluxes in the growing season with an opaque static chamber. The results showed that ① Grazing had no effect on CO₂ and N₂O fluxes during the first year of grazing treatment. ② However, grazing decreased soil water content (P<0.05), moderate grazing intensity decreased microbial biomass carbon (P<0.05), and moderate and heavy grazing intensities reduced microbial biomass nitrogen (P<0.05). ③ Significant positive correlations between CO₂ flux and soil temperature and soil moisture were observed. The correlation between temperature and CO₂ emissions was increased by grazing. ④ There was a significant positive correlation between soil temperature, soluble nitrogen, soil microbial biomass nitrogen, CO₂ flux, and N₂O flux. Our results indicated that GHG, regulated by soil microorganisms, was affected by soil temperature and moisture.

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