水保所知识产出(1956---)知识库

放牧是高寒草甸一种重要的利用方式，对土壤理化性质和植被会产生重要影响，研究放牧对高寒草甸生态系
统呼吸的影响对估算碳交换和制定合理放牧政策具有重要意义. 利用静态箱-气象色谱法，于2012年8月到2013年7月
在青藏高原东缘高寒草甸对轻度、中度和重度3种放牧强度下的生态系统呼吸进行每月至少一次的连续观测，以估算
高寒草甸生态系统呼吸，并探讨放牧强度对生态系统呼吸的作用. 结果显示：轻度、中度和重度放牧条件下，年均生态
系统呼吸（以C计）分别为226.33 ± 62.30、213.63 ± 53.22和215.15 ± 53.19 mg m -2 h -1 ，三者之间无显著差异（P > 0.05）；在
生长季生态系统呼吸分别为367.97 ± 47.86、324.62 ± 44.95和348.37 ± 43.10 mg m -2 h -1 ，在非生长季生态系统呼吸分别为
105.81 ± 22.13、96.55 ± 14.69和110.61 ± 16.89 mg m -2 h -1 ，在不同放牧强度下生态系统呼吸均表现出明显的季节特征，但
在相同季节不同放牧强度间生态系统呼吸差异不显著；月累积降水量与生态系统呼吸呈显著正相关关系；该区域放
牧地生态系统平均年累积呼吸为472.63 g m -2 h -1 . 本研究表明，在试验初期不同放牧强度对生态系统呼吸无显著作用.
（图3 表2 参32）

Carbon dioxide (CO 2 ) is one of the most important greenhouse gases and its emission has been increasing from the
Industrial Revolution. This situation has attracted considerable attention among scientists. Alpine meadow is an important
ecosystem styles in the Qinghai-Tibetan Plateau and is a sensitive trigger of human activities. Grazing is one of the most
important land-use types. So we conducted an experiment to investigate the influence of different grazing intensity on
ecosystem respiration (Re) in alpine meadows. Using static chambers and gas chromatography, we measured the Re under
light grazing intensity (L), moderate grazing intensity (M) and heavy grazing intensity (H) from August 2012 to July 2013
(twice a month in July, August and September; once a month in other time of the year). The result showed an annual mean
Re as 226.33 ± 62.30, 213.63 ± 53.22 and 215.15 ± 53.19 mg m -2 h -1 under L, M and H, respectively. However, the mean Re
showed no significant difference under different grazing intensities. In the growing season, Re under L, M and H was 367.97 ±
47.86, 324.62 ± 44.95 and 348.37 ± 43.10 mg m -2 h -1 , respectively. In non-growing season, it was 105.81 ± 22.13, 96.55 ± 14.69
and 110.61 ± 16.89 mg m -2 h -1 , respectively. The variation of Re showed obvious seasonal characteristics, but not significantly  related to the grazing intensity. Temperature in soil surface, 5 cm depth and 10 cm depth showed a positive but not significant
correlation with Re. Month cumulative precipitation exhibited a significant and positive correlation with Re. The average annual
total Re in this region was 472.63 g m -2 a -1 . At the early stage of the experiment, the grazing intensity did not significantly affect
Re in the alpine meadow ecosystem. Compared with temperature, precipitation had a stronger impact on Re.