高寒草甸生态系统降雨事件对不同深度土壤碳释放的试验分析  

Experimental analysis of soil carbon release at different depths by rainfall events in alpine meadow ecosystem

作　　者：邓钰婧 李小雁 胡霞 吴秀臣 王佩 DENG Yujing;LI Xiaoyan;HU Xia;WU Xiuchen;WANG Pei(School of Natural Resources,Faculty of Geographical Science,Beijing Normal University,Beijing 100875,China;State Key Laboratory of Earth Surface Processes and Resource Ecology,Faculty of Geographical Science,Beijing Normal University,Beijing 100875,China)

机构地区：[1]北京师范大学地理科学学部自然资源学院,北京100875 [2]北京师范大学地理科学学部地表过程与资源生态国家重点实验室,北京100875

出　　处：《生态学报》2022年第8期3315-3324,共10页Acta Ecologica Sinica

基　　金：国家自然科学基金重点项目(41730854)。

摘　　要：以青藏高原高寒草甸生态系统为研究对象,基于LI-8150土壤CO_(2)通量全自动连续测量系统及实验设计,对不同深度的土壤碳释放进行了连续原位观测,分析了晴天和5次持续性降水条件下不同深度土壤碳释放特征,结合土壤温湿度的观测,解析了降雨对不同深度土壤碳释放的影响及机理。结果表明:(1)在0 cm、20 cm、40 cm、70 cm深度处,土壤碳释放均呈现明显的单峰曲线变化特征,其日均值(±标准差)分别为(3.96±0.89)μmol m^(-2)s^(-1)、(5.09±1.79)μmol m^(-2)s^(-1)、(7.83±1.95)μmol m^(-2)s^(-1)和(4.43±1.6)μmol m^(-2)s^(-1)。(2)降雨提高了土壤含水量,显著抑制了土壤碳释放,且对深层的抑制作用显著大于表层。其中,第5次持续性降水事件对土壤水分的补充作用最明显(增量最大),其对土壤碳释放的抑制作用也更显著,并出现负通量(即碳吸收)。随着土壤深度的增加,观测到碳吸收现象愈加显著。(3)不同深度土壤碳释放与土壤温度、水分呈指数或二次曲线相关关系。晴天条件下,土壤含水量较稳定,土壤温度是影响各层土壤碳释放的主导因子;而降雨条件下,土壤含水量变化显著,土壤水分成为主导土壤碳释放的关键因子,并对其可能产生的机理进行了讨论。This study selected Qinghai-Tibet Plateau alpine meadow ecosystem as the research object. Based on the Li-8150 automated soil CO_(2) flux system, continuous in-situ observation of soil carbon release at different depths was carried out, and the characteristics of soil carbon release at different depths in sunny and 5 times of continuous rain events were analyzed. Combined with the observation of soil temperature and soil moisture, the effects of rainfall on soil carbon release at different depths and possible mechanisms were analyzed. The results showed that,(1) The soil respiration at 0 cm, 20 cm, 40 cm, and 70 cm all showed obvious single-peak curve, and their daily average soil respiration(±standard deviation) were(3.96±0.89) μmol m^(-2)s^(-1),(5.09±1.79) μmol m^(-2)s^(-1),(7.83±1.95) μmol m^(-2)s^(-1)and(4.43±1.6) μmol m^(-2)s^(-1).(2) Rainfall significantly increased soil moisture, and inhibited soil carbon release, and the inhibition effects of deep layer was significantly greater than that of surface layer. Among them, the fifth persistent rain event had the most obvious supplementary effect on soil moisture(the largest increment), and its inhibitory effect on soil carbon release was also more significant, even negative flux(i.e., carbon sequestration) appeared in the deep layer. With the increase of soil depth, carbon absorption was observed to be more significant.(3) The relationship between soil carbon release at different depths and soil temperature or soil moisture was correlated with the exponential correlation or quadratic curve. Under sunny conditions, the soil moisture is stable, and the soil temperature is the dominate factor to affect the surface soil respiration. While under rainfall days, soil moisture changed significantly, and became the control of soil carbon release, and its possible mechanism was discussed.

关 键 词：土壤呼吸 碳吸收 降水 土壤温度 土壤含水量 

分 类 号：S812.2[农业科学—草业科学]