Effects of grazing exclusion on soil respiration components in an alpine meadow on the north-eastern Qinghai-Tibet Plateau

文献类型： 外文期刊

第一作者： Wang, Jinlan

作者： Wang, Jinlan;Liu, Yuzhen;Cao, Wenxia;Li, Wen;Wang, Xiaojun;Zhang, Degang;Shi, Shangli;Pan, Duofeng;Liu, Wenlan

作者机构：

关键词： Alpine meadow; Grazing exclusion; Soil respiration; Heterotrophic respiration; Autotrophic respiration

期刊名称：CATENA （ 影响因子：5.198； 五年影响因子：5.594 ）

ISSN： 0341-8162

年卷期： 2020 年 194 卷

页码：

收录情况： SCI

摘要： Grazing exclusion has been widely used to restore degraded grasslands worldwide. Total soil respiration (Rs) (consisting of heterotrophic respiration (Rh, microbes and soil fauna respiration) and autotrophic respiration (Ra, plant root and their symbionts respiration)) play a critical role in the global carbon (C) balance. Quantifying Rs, Rh and Ra in relation to different grazing exclusion durations is vital to better understanding the impact of grassland management on global C cycling. However, how Rs and its components respond to different grazing exclusion durations remain unclear. Therefore, in this study, a trenching method was used to separate the Ra and Rh in an alpine meadow with different grazing exclusion durations (0, 4, 7, 10 and 12 years) on the north-eastern Qinghai-Tibet Plateau. Our results demonstrated that the growing season Rs, Rh and Ra showed nonlinear (hump-shaped) response patterns with the length of grazing exclusion, with a peak point at the 7-year grazing exclusion. Meanwhile, grazing exclusion treatments significantly increased the Rs, Rh and Ra compared to the grazed site. Grazing exclusion substantially increased the soil respiration temperature sensitivity (Q(10)) values of Rs, Rh and Ra. Moreover, the Q(10) values of Ra and Rh showed hump-shaped response patterns with the length of grazing exclusion, with a threshold of 7 years grazing exclusion. The annual Ra/Rs ratio ranged from 53% to 69% during the growing season, indicating that changes in soil respiration were mainly determined by changes in autotrophic respiration. In addition, soil temperature could better explain Rh (R-2 = 0.89-0.94) than Ra (R-2 = 0.84-0.9). Our research highlights the nonlinear response of Rs, Rh and Ra to the length of grazing exclusion, and suggests that different grazing exclusion durations should be considered for better evaluating the impact of grassland management on global C cycling on the north-eastern Qinghai-Tibet Plateau.

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