CO_2浓度升高和N沉降对中亚热带森林土壤呼吸的短期影响  

Short-term effects of CO_2 elevation and N deposition on soil respiration in a mid-subtropical forest

作　　者：张方月 王清奎[1,2] 于小军[2] 

机构地区：[1]森林与土壤生态国家重点实验室中国科学院沈阳应用生态研究所,沈阳110164 [2]中国科学院会同森林生态实验站,湖南会同418307 [3]中国科学院大学,北京100049

出　　处：《生态学杂志》2015年第6期1638-1643,共6页Chinese Journal of Ecology

基　　金：国家重点基础研究发展计划项目(2012CB416905);中国科学院战略性先导科技专项(XDA05070305)资助

摘　　要：大气CO2浓度升高和N沉降持续增加已是不争的事实,影响着森林生态系统碳循环。为深入了解CO2浓度升高和N沉降增加对中亚热带森林土壤碳循环的共同影响,本研究通过模拟CO2浓度升高和N沉降增加,利用Li-Cor 8100测定了土壤呼吸1年的变化。结果表明:CO2浓度升高和N沉降显著促进了土壤呼吸,其单独处理的土壤呼吸速率分别比对照高24.4%和27.9%(P<0.01);CO2浓度升高和N沉降同时作用下,土壤呼吸速率比对照高46.5%(P<0.01)。表明,N沉降和CO2浓度升高对土壤呼吸的促进作用存在非加和效应。相关性分析显示,土壤呼吸与土壤温度呈显著正相关,而与土壤含水量呈负相关。CO2浓度升高和N沉降增加改变了土壤呼吸的温度敏感性。CO2浓度升高略微增加了土壤呼吸的温度敏感性,而N沉降则降低了土壤呼吸的温度敏感性。因此,在全球CO2浓度升高和N沉降增加的背景下,中亚热带森林土壤有机碳向大气中的排放可能会增加,但有机碳分解对环境温度变化的敏感性降低。Carbon cycling in forest ecosystem can be influenced by atmospheric carbon dioxide（ CO2） elevation and nitrogen（ N） deposition. A simulation experiment was conducted to investigate the effect of CO2 elevation and N deposition on soil carbon cycling in mid-subtropical forests.In this experiment,soil respiration was measured for one year using Li-Cor 8100 infrared gas analyzer. Compared with the control treatment,soil respiration rate was respectively increased by24.4% and 27. 9% in CO2 elevation and N deposition treatments,while it was increased by46.5% in the combined treatment of CO2 elevation and N deposition. Correlation analysis showed that soil respiration was significantly positively correlated to soil temperature and negatively to soil moisture. The temperature sensitivity of soil respiration was also affected by CO2 elevation and N deposition. The temperature sensitivity of soil respiration was slightly increased by CO2 elevation,but decreased by N deposition. Our findings suggest that the release of soil organic carbon to the atmosphere through soil respiration is possibly increased in the context of CO2 elevation and N deposition in mid-subtropical forest ecosystems,and the sensitivity of the response of soil organic carbon decomposition to changes in environmental temperature is decreased.

关 键 词：气候变化 土壤碳循环 温度敏感性 交互作用 

分 类 号：S714[农业科学—林学]