International Joint Research Laboratory for Global Change Ecology, School of Life Sciences, Henan University, Kaifeng, Henan 475004, China.
School of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China.
Sci Rep. 2017 Mar 31;7:45782. doi: 10.1038/srep45782.
Extreme precipitation events are predicted to occur more frequently and will have significant influences on terrestrial ecosystem carbon (C) cycling in the future. However, response patterns of soil respiration to precipitation changes remain uncertain in terrestrial ecosystems. A field experiment with seven precipitation treatments (i.e. from -60% to +60% of ambient precipitation to form a drought to wet precipitation gradient) was conducted over three growing seasons (2010-2012) in a semiarid temperate steppe of Northern China. Results showed a nonlinear response pattern of soil respiration along the experimental precipitation gradient, with soil respiration suppressed by decreased precipitation and enhanced by increased precipitation. Over the three growing seasons, soil respiration was reduced more under the three drought treatments (by 45.8, 32.8, and 15.9% under the -60, -40, and -20% treatments, respectively) than stimulated under the three wet treatments (by 8.9, 14.3, and 18.5% under the +20, +40, and +60% treatments, respectively). Our results indicate that soil respiration was more sensitive to decreased than increased precipitation treatments. The nonlinear and asymmetric responses of soil respiration to precipitation changes should be built into ecosystem models to project ecosystem C cycling associated with climate change.
极端降水事件预计将更频繁地发生，并将对未来陆地生态系统碳（C）循环产生重大影响。然而，陆地生态系统中土壤呼吸对降水变化的响应模式仍不确定。在中国北方半干旱温带草原进行了为期三个生长季（2010-2012 年）的七个降水处理（即从环境降水的-60%到+60%形成干旱到湿润降水梯度）的野外实验。结果表明，土壤呼吸沿着实验降水梯度呈现出非线性响应模式，降水减少会抑制土壤呼吸，而降水增加则会增强土壤呼吸。在三个生长季中，三种干旱处理（-60%、-40%和-20%处理下分别减少了 45.8%、32.8%和 15.9%）下的土壤呼吸减少量大于三种湿润处理（+20%、+40%和+60%处理下分别增加了 8.9%、14.3%和 18.5%）。我们的结果表明，土壤呼吸对减少降水的处理比增加降水的处理更为敏感。土壤呼吸对降水变化的非线性和不对称响应应纳入生态系统模型，以预测与气候变化相关的生态系统 C 循环。
