施氮对青藏高原东缘窄叶鲜卑花灌丛土壤呼吸的影响  

Effects of nitrogen addition on soil respiration of Sibiraea angustata shrub in the eastern margin of Qinghai-Tibetan Plateau

作　　者：李娇[1,2] 尹春英[1] 周晓波[3] 魏宇航[1] 高巧[1] 刘庆[1] 

机构地区：[1]中国科学院成都生物研究所,中国科学院山地生态恢复与生物资源利用重点实验室,生态恢复与生物多样性保育四川省重点实验室,成都610041 [2]中国科学院大学,北京100049 [3]四川省理县林业局,理县623100

出　　处：《生态学报》2014年第19期5558-5569,共12页Acta Ecologica Sinica

基　　金：中国科学院战略性先导科技专项(XDA05050303);国家自然科学基金项目(31070533);中国科学院方向项目(KSCX2-EWJ-22);国家科技支撑计划专题(2011BAC09B04-01)

摘　　要：开展土壤呼吸对大气氮沉降增加的响应研究对预测陆地生态系统碳循环具有重要意义。采用外施氮肥模拟氮沉降,结合壕沟法分离土壤呼吸组分,研究青藏高原东缘主要的灌丛类型——窄叶鲜卑花(Sibiraea angustata)灌丛土壤呼吸对不同施氮水平(N0(对照)、N2、N5和N10分别相当于0、2、5和10 g N m-2a-1浓度的氮沉降)的短期响应。结果表明:试验期间(2012年5—10月份),(1)土壤呼吸呈现明显的季节变化,施氮对生长季土壤总呼吸、异养呼吸无显著影响,而对自养呼吸有显著的抑制作用(P<0.05)。(2)土壤呼吸也存在显著的日变化,施氮对一天中土壤总呼吸及其组分均有显著影响(P<0.001)。总体上,施氮促进了土壤总呼吸、异养呼吸,而抑制了自养呼吸。(3)施氮对土壤总呼吸、异养呼吸平均每月排放CO2通量无显著影响,而对自养呼吸平均每月排放CO2通量有显著的抑制作用(P<0.05),并在不同月份对土壤呼吸及其组分的影响不同。(4)土壤总呼吸、异养呼吸与地下5 cm土壤温度之间具有较好的指数关系(P<0.001),而与土壤含水量相关性较弱。关于土壤呼吸各组分对大气氮沉降响应差异的机理有待进一步研究。The response of soil respiration to the increasing nitrogen deposition plays an important role in predicting carbon cycle of terrestrial ecosystems. To date, however, few studies have been addressed to soil respiration changes in shrub ecosystem compared with forest and grassland ecological system. In this study, we subjected Sibiraea angustata shrub ecosystem, the main type in the eastern margin of Qinghai-Tibetan Plateau, to four nitrogen addition levels practiced within 5 m×5 m plot： N2（2 g N m^-2 a^-1） , N5（5 g N m^-2 a^-l） , N10（10 g N m^-2 a^-1） and No（control, add the same volume of water without nitrogen in other treatments）, respectively. Ditching method was used to separate the different components of soil respiration. Plant root respiration was defined as autotrophic respiration, while soil microbial and animal respirations were defined as heterotrophic respiration. Changes of soil respiration to the short-time N addition were measured during the growing season, with the soil moisture at 5 cm and 10 cm depth measured at the same time. The results showed： （1） Soil respiration （total, heterotrophic and autotrophic respiration） showed apparent seasonal variation during the experimental period （2012.5--2012.10）. During the growth season, nitrogen addition had no significant effects on total and heterotrophic respiration （P〉0.05）, while it remarkably inhibited the autotrophic respiration （P〈0.05）. It turned out that the soil respiration rates under N2 and N10 treatment was lower than N0 treatment by 0.31 and 0.23 μmol m^-2 s^-1, respectively. Meanwhile, the soil respiration rates under N5 and N0 treatment exhibited no obvious difference. （2） Soil respiration （the total, heterotrophic and autotrophic respiration） showed apparent diurnal variation. Nitrogen addition had significant effects on the total, heterotrophic and autotrophic respiration （P〈0.001） in the whole day. Nitrogen addition remarkably promoted the heterotrophic respiration, with soil

关 键 词：窄叶鲜卑花灌丛 施氮 土壤总呼吸 异养呼吸 自养呼吸 Q10 

分 类 号：S154[农业科学—土壤学]