Shen Yan, Sun Jian-Ping, Luo Yu-Kun, Diao Hua-Jie, Yan Wei-Dong, Wang Chang-Hui, Dong Kuan-Hu
College of Animal Science and Veterinary Medicine, Shanxi Agricultural University, Taigu 030801, China.
State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.
Huan Jing Ke Xue. 2018 Nov 8;39(11):5237-5245. doi: 10.13227/j.hjkx.201803213.
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 NO 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 CO and NO fluxes during the first year of grazing treatment. ② However, grazing decreased soil water content (<0.05), moderate grazing intensity decreased microbial biomass carbon (<0.05), and moderate and heavy grazing intensities reduced microbial biomass nitrogen (<0.05). ③ Significant positive correlations between CO flux and soil temperature and soil moisture were observed. The correlation between temperature and CO emissions was increased by grazing. ④ There was a significant positive correlation between soil temperature, soluble nitrogen, soil microbial biomass nitrogen, CO flux, and NO flux. Our results indicated that GHG, regulated by soil microorganisms, was affected by soil temperature and moisture.
放牧是中国北方草原管理的最重要方式之一。不同的研究聚焦于放牧对生态系统结构和功能的影响。放牧通过生物和物理过程影响土壤结构和功能，如动物践踏、采食和排泄，进而影响一氧化氮排放。然而，关于中国北方半干旱草原生态系统中放牧强度对温室气体（GHGs）排放的研究较少。在本研究中，在中国北方典型农牧交错区（山西右玉）的半干旱草原生态系统中考虑了四种不同的放牧强度。通过在生长季节使用不透明静态箱测量温室气体通量，研究了不同放牧强度对温室气体通量的影响。结果表明：① 在放牧处理的第一年，放牧对一氧化碳和一氧化氮通量没有影响。② 然而，放牧降低了土壤含水量（<0.05），适度放牧强度降低了微生物生物量碳（<0.05），适度和重度放牧强度降低了微生物生物量氮（<0.05）。③ 观察到一氧化碳通量与土壤温度和土壤湿度之间存在显著正相关。放牧增加了温度与一氧化碳排放之间的相关性。④ 土壤温度、可溶性氮、土壤微生物生物量氮、一氧化碳通量和一氧化氮通量之间存在显著正相关。我们的结果表明，由土壤微生物调节的温室气体受土壤温度和湿度的影响。
