摘要
降雨作为一个重要的环境因子,对土壤呼吸具有重要的影响。研究土壤呼吸与降雨的关系,对准确估算大气中的CO2含量具有重要意义。本研究通过人工模拟降雨事件,应用野外原位测定方法,测量了热带次生林和橡胶林土壤呼吸速率、地下5cm土壤温度和土壤含水量的变化,以探究热带两种主要植被类型的土壤呼吸、土壤温度、土壤含水量对旱季单次降雨事件的响应过程与规律。研究发现,在旱季连续一周没有降雨的情况下,人工模拟降雨事件使土壤呼吸在降雨后的2h内被迅速激发,次生林的土壤呼吸最大达到11.15 μmolCO2·m-2·s-1,是对照的近7倍;橡胶林的土壤呼吸最大达到了15.88 μmolCO2·m-2·s-1,是对照的近11倍。随后激发效应迅速降低,尤其是橡胶林,在人工模拟降雨6h后处理与对照间无显著差异。人工模拟降雨前两种林型的土壤含水量与对照相比均无显著性差异,人工模拟降雨后的2d内土壤含水量均显著高于对照;人工模拟降雨前后土壤温度与对照相比均无显著性差异。本研究结果支持了"Birch effect",2种主要热带林型在旱季时期,由于单次降雨事件激发而释放到大气中的CO2是降雨前的数倍。
Rainfall has important effects on soil respiration. To understand the relationship between rainfall and soil respiration is of significance in accurately estimating carbon flux. In this paper, an in situ observation was conducted in a tropical secondary forest and a rubber plantation in Xishuangbanna of Yunnan to measure the soil respiration rate and the soil temperature and moisture content at the depth 5 cm after a simulated rainfall, aimed to understand the responses of the soil respiration, soil temperature, and soil moisture content under the two main vegetation types to the simulated rainfall. Under the condition of one week no-rainfall in dry season, the soil respiration was rapidly stimulated 2 hours after the rainfall, with the maximum soil respiration rate in the secondary forest rubber plantation reached 11.15 and 15.88 μmol CO2·m-2·s-1, being 7 and 11 times greater than that of the control, respectively. This effect decreased through time, particularly in rubber plantation where the difference with the control was not significant 6 hours after the rainfall. Two days after the simulated rainfall, the soil moisture contents in the tropical secondary forest and rubber plantation were significantly higher than the control, but the soil temperature had less difference. This study supported the ＂Birch effect＂, and showed that due to the rainfall event, the CO2 release from the two major tropical forest types in dry season was increased several folds.
出处
《生态学杂志》
CAS
CSCD
北大核心
2012年第8期1887-1892,共6页
Chinese Journal of Ecology
基金
中国科学院战略性先导科技专项(XDA05070303
XDA05050601)
国家重点基础研究发展计划项目(2010CB833501)
国家自然科学基金项目(41071071)资助
关键词
单次人工降雨
土壤呼吸
土壤温度
土壤含水量
single artificial rainfall
soil respiration
soil temperature
soil moisture content
