固沙植被区两类结皮斑块土壤呼吸对降雨脉冲的响应

doi:10.7522/j.issn.1000-694X.2014.00009

摘要/Abstract

摘要：

与降水事件密切相关的土壤水分有效性是荒漠生态系统土壤呼吸的重要驱动因子。研究了固沙植被区以藓类和藻类为主的生物土壤结皮斑块土壤呼吸对模拟降雨(5、10、20 mm)的响应。结果表明:3种降雨量对不同结皮斑块土壤呼吸均有显著的激发作用, 但2种土壤的响应特征不同。藓类结皮斑块土壤呼吸速率在降雨后0.5 h达到最大值, 而藻类结皮斑块土壤在降雨后2 h达到最大值, 其呼吸速率分别是降雨前土壤呼吸速率的43~58、21~25倍,随后, 两类结皮斑块土壤呼吸速率逐渐下降并恢复到降雨前水平。随着降雨量的增加, 藓类结皮斑块土壤最大呼吸速率和平均呼吸速率显著增大, 而藻类结皮斑块土壤则无明显变化; 2种土壤碳释放量均随着降雨量的增大而增加。在相同降雨条件下, 藓类结皮斑块土壤呼吸速率峰值和平均值及碳释放量均显著大于藻类结皮斑块土壤。表明生物土壤结皮和降雨量均对荒漠生态系统土壤呼吸起着重要的调控作用。

关键词: 土壤呼吸, 降雨, 生物土壤结皮, 固沙植被区, 腾格里沙漠

Abstract:

In arid and semiarid region, soil water availability, which is closely related to precipitation, is the major driver of soil respiration. In this study, different simulated precipitations (5, 10, 20 mm) were applied to two biologically crusted soils to investigate soil CO₂ efflux in response to precipitation pulse in these regions. The results showed that three levels of rainfall significantly stimulated CO₂ efflux from both biologically crusted soils. However, the response patterns varied between crust types. After rainfall, the respiration rates of moss and algal overlying soils reached their maximum within 0.5 h and 2 h, respectively. The peak values were 43-58 and 21-25 times greater than the background levels. After it reached the peak, soil CO₂ efflux gradually decreased and returned to background level. The peak and average respiration rates of moss crusted soils significantly increased with the amount of water added, while these parameters did not vary with experimental pulse in algae crusted soil. Total carbon release of both biologically crusted soils increased with precipitation size. Following the same amount of water addition, peak and average respiration rates as well as total carbon emissions of moss overlying soils were significantly greater than the algae ones. Our results suggest that biological soil crusts and precipitation can co-regulate soil CO₂ efflux.

Key words: soil respiration, precipitation, biological soil crust, fixed sand dunes, Tengger Desert

中图分类号:

S154.36

赵蓉, 李小军, 赵洋, 杨昊天, 李刚. 固沙植被区两类结皮斑块土壤呼吸对降雨脉冲的响应[J]. 中国沙漠, 2015, 35(2): 393-399.

Zhao Rong, Li Xiaojun, Zhao Yang, Yang Haotian, Li Gang. CO₂ Efflux from Two Typies Biologically Crusted Soil in Response to Simulated Precipitation Pulses in the Tengger Desert[J]. JOURNAL OF DESERT RESEARCH, 2015, 35(2): 393-399.

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