模拟氮沉降对武夷山亚热带常绿阔叶林土壤呼吸的影响  

Soil Respiration and Its Response to Simulated Nitrogen Deposition in A Subtropical Evergreen Broad-leaved Forest in Mount Wuyi

作　　者：孙海燕[1] 赵俊平[1] 肖艳玲[1] 冯建伟 张占贵 SUN Haiyan;ZHAO Junping;XIAO Yanling;FENG Jianwei;ZHANG Zhangui(School of Economics and Management,Northeast Petroleum University,Daqing 163318,China;International Cooperation Department,Northeast Petroleum University,Daqing 163318,China;College of Forestry,Agricultural University of Hebei,Baoding 071001,China)

机构地区：[1]东北石油大学经济管理学院,黑龙江大庆163318 [2]东北石油大学国际交流合作处,黑龙江大庆163318 [3]河北农业大学林学院,河北保定071001

出　　处：《生态环境学报》2018年第9期1632-1638,共7页Ecology and Environmental Sciences

基　　金：东北石油大学科研基金项目(rc201734)

摘　　要：大气氮沉降是全球变化的焦点问题之一,为研究大气氮沉降对森林生态系统土壤呼吸的影响,在武夷山亚热带常绿阔叶林进行人工模拟氮沉降,设置对照(N0,0 kg·hm^(-2)·a^(-1))、低氮(N1,50 kg·hm^(-2)·a^(-1))、中氮(N2,100 kg·hm^(-2)·a^(-1))和高氮(N3,150 kg·hm^(-2)·a^(-1)),采用Li-6400分析系统测定土壤呼吸速率,同时测定土壤温度和土壤含水量,探讨氮沉降的背景下土壤温度和土壤含水量与土壤呼吸的关系。结果表明,(1)亚热带常绿阔叶林土壤呼吸速率具有明显的季节动态变化,土壤呼吸速率均为1月最低,8月最高。(2)常绿阔叶林土壤总呼吸存在明显的季节格局,总体呈单峰型,其峰值均出现在8月,重复测量方差分析结果显示,在生长季,氮沉降对土壤总呼吸均无显著影响(P>0.05)。(3)常绿阔叶林土壤总呼吸与土壤温度呈显著的指数关系,其响应具体表现在,低高氮(N1,N3)处理和中氮(N2)处理在一定程度上分别提高和降低了土壤呼吸Q_(10)。N0、N1、N2、N3处理下土壤总呼吸的Q_(10)分别为1.52、1.57、1.44、1.56;土壤呼吸速率与0~5 cm和5~10 cm土层土壤含水量之间的关系用二次曲线拟合的效果最好,其决定系数R^2分别为0.156~0.354和0.239~0.387,明显低于土壤呼吸速率与土壤温度关系方程的R^2值,这表明土壤呼吸速率与土壤含水量之间的相关性较弱,由此可知土壤含水量对土壤呼吸的影响远小于土壤温度对土壤呼吸的影响。(4)N0、N1、N2和N3处理的土壤总呼吸年碳排放量分别为5.67、5.98、6.22和4.22 t·hm^(-2)·a^(-1),低氮和中氮处理的排放比对照高出5.46%和9.70%,低氮促进了土壤呼吸年通量,而高氮抑制了土壤呼吸年通量;方差分析结果表明,氮沉降对土壤呼吸、异养呼吸年通量有显著影响,其中N2对土壤呼吸、异养呼吸年通量影响最大(P<0.05)。Atmospheric nitrogen deposition is one of the focus issue of global change,and this study was conducted in a subtropical evergreen broad-leaved forest in Mount Wuyi aiming at measuring soil respiration and the effects of nitrogen deposition on soil CO2 emission.Nitrogen addition experiments were carried out within the forest selected for 12 months by Li-6400.Four N addition treatments(in three replicates)were established in mature forest:control,No N(N0,0 kg·hm-2·a-1),low N(N1,50 kg·hm-2·a-1),medium N(N2,100 kg·hm-2·a-1)and High N(N3,150 kg·hm-2·a-1).Meanwhile,we measured temperature and soil moisture to explore the response of soil temperature and soil moisture to soil respiration in this region.The results showed that,(1)Soil respiration in a subtropical evergreen broad-leaved forest in Mount Wuyi had the obvious seasonal dynamics and there was a lower soil respiration in January and higher soil respiration in August.(2)There was an obvious seasonal dynamics in soil respiration,and soil respiration showed the unimodal curve with the peak in August.Repeated measurement of variance results showed that there was no significant effect of nitrogen deposition on soil respiration(P>0.05).(3)There was a significantly exponential relationship between total soil respiration and soil temperature,while N1,N3 increased Q10 and N2 decreased Q10,and the Q10 in N0,N1,N2,N3 was 1.52,1.57,1.44 and 1.56,respectively.There was a significantly quadratic curve between total soil respiration and soil water content in 0~5 cm and 5~10 cm,and R2 was 0.156~0.354,0.239~0.387,which was higher than the correlation coefficient between total soil respiration and soil temperature,indicating that the effect of soil water content on soil respiration was weak than soil temperature.And(4)the total soil respiration carbon emission in N0,N1,N2,N3 was 5.67,5.98,6.22 and 4.22 t·hm-2·a-1,respectively.Lower N promoted soil respiration and higher N inhibit soil respiration.Variance analysis showed that nitrogen deposition had no significant eff

关 键 词：武夷山 常绿阔叶林 土壤呼吸 氮沉降 

分 类 号：S714[农业科学—林学] X171.1[环境科学与工程—环境科学]