基于室内试验的土壤呼吸温度敏感性影响因素整合分析

Meta-analysis of the Factors Affecting Soil Respiration Temperature Sensitivity Based on Indoor Measurements

本研究利用整合分析法收集了近15年来在全球范围内开展的相关领域研究成果,建立土壤呼吸温度敏感性(Q_(10))数据库;同时获取环境因子变量,包含初始温度、增温幅度、增温时间、土壤含水率、土壤有机质含量、土壤氮含量、土壤p H值、年均温、年均降水量、海拔、纬度、生态系统类型。分别分析了不同生态系统类型下的Q_(10)差异,并通过线性混合模型和随机森林模型分析各因子对Q_(10)的影响程度和变量重要性评分。结果表明:不同生态系统的Q_(10)值之间存在显著差异(P<0.05),全球土壤呼吸Q_(10)均值为1.92。Q_(10)在不同生态系统中均值大小分别为:森林(1.70)、草甸(1.88)、农田(2.79)、湿地(1.53)、荒漠(2.18)、极地(2.02)。初始温度、增温幅度、增温时间、土壤含水率、土壤pH值、年均温对Q_(10)的影响具有显著性(P<0.05)。其中Q_(10)随初始温度的升高而降低;增温幅度较大时,Q_(10)值较小;Q_(10)随增温时间的增加出现先升高后降低的趋势;土壤含水率、土壤pH值和年均温对Q_(10)有正向影响。在影响土壤呼吸Q_(10)的环境指标中,初始温度>土壤pH值>增温幅度>土壤含水率>纬度>土壤有机质>海拔>土壤氮含量>年均降水量>年均温>增温时间。其中,初始温度、土壤p H值是Q_(10)的主要驱动因子,变量重要性分别为20.6%和19.9%。本研究可为进一步探索气候变化条件下土壤呼吸规律提供参考。

In this study, we collected research findings in correlative field at a global scale over the past 15 years based on the meta-analysis method, and soil respiration temperature sensitivity(Q_(10)) database was established. The obtained environment factor variables including: initial temperature, temperature increase content, incubation time, soil moisture content, soil organic matter content, soil nitrogen content, soil pH value, average annual temperature, average annual precipitation, altitude, latitude and ecosystem classification. In this paper, we focus on the Q_(10)variation at different ecosystem and the extent of Q_(10)influenced by the different environment factor variables. A comprehensive analysis has been made through the linear mixed model and random forest regression, the result shows that there are significant differences in Q_(10)values among different ecosystems(P <0.05), and the mean value of global soil respiration Q_(10)is 1.92. The average values of Q_(10)in different ecosystems are: forest(1.70), meadow(1.88), farmland(2.79), wetland(1.53), desert(2.18), polar region(2.02). The initial temperature, temperature increase range, temperature increase time, soil moisture content, soil pH and annual average temperature have significant effects on Q_(10)(P<0.05). Among them, Q_(10)decreases with the increase of the initial temperature;when the temperature increase is large, the value of Q_(10)is small;Q_(10)increases first and then decreases with the increase of the temperature increase;soil moisture content, soil pH and annual average temperature have a positive effect on Q_(10). The effects of different environmental factors on Q_(10)is initial temperature >soil pH value > temperature increase content > soil moisture content > latitude > soil organic matter content > altitude > soil nitrogen content > annual average precipitation > annual average temperature > incubation time. It is noted that the initial temperature and soil pH content are the main driving factors of Q_(10), the contributions to Q_(10)change is 20.6% and 19.9%, respectively. This study can provide reference for further exploration of soil respiration under climate change.