增温、施氮对中亚热带杉木林土壤可溶性有机质的影响  

Effects of Soil Warming and Nitrogen Addition on Soil Dissolved Organic Matter of Cunninghamia lanceolata Plantations in Subtropical China

作　　者：焦宏哲 李欢[1,2] 陈惠 鲍勇 孙颖 杨玉盛 司友涛[1,2] JIAO Hongzhe;LI Huan;CHEN Hui;BAO Yong;SUN Ying;YANG Yusheng;SI Youtao(School of Geographical Sciences,Fujian Normal University,Fuzhou 350007,China;Cultivation Base of State Key Laboratory of Humid Subtropical Mountain Ecology,Fuzhou 350007,China)

机构地区：[1]福建师范大学地理科学学院,福州350007 [2]湿润亚热带山地生态国家重点实验室培育基地,福州350007

出　　处：《土壤学报》2020年第5期1249-1258,共10页Acta Pedologica Sinica

基　　金：国家自然基金面上项目(31570606);福建省自然科学基金面上项目(2019J01282,2015J01120)资助。

摘　　要：受人类活动的影响,1880-2012年,全球地表平均温度约提高0.85°C;同时,1980-2010年间我国大气氮沉降以0.41 kg·hm^–2的速率逐年增加。全球变暖和大气氮沉降将通过影响环境因子变化进而影响土壤可溶性有机质(DOM,Dissolved organic matter)。为探究增温和施氮对DOM数量及其结构的影响,选取我国中亚热带杉木人工林土壤进行增温以及施氮试验,试验设对照(CT,0 kg·hm^–2·a^–1)、增温(W,+5℃,0 kg·hm^–2·a^–1)、高氮(HN,80 kg·hm^–2·a^–1)、低氮(LN,40 kg·hm^–2·a^–1)、增温×高氮(WHN,+5℃,80 kg·hm^–2·a^–1)、增温×低氮(WLN,+5℃,40 kg·hm^–2·a^–1)6种处理。结果表明,与CT相比,W处理的土壤可溶性有机碳(DOC,Dissolved organic carbon)和可溶性有机氮(DON,Dissolved organic nitrogen)增加,但其芳香性指数和腐殖化程度低,这很可能是由于增温促进了土壤有机质(SOM,Soil organic matter)向DOM的转化。季节通过影响土壤环境,对施氮后的土壤DOM结构有不同影响:干季(2015年1月)时,施氮使DOM含量增加,其芳香性指数显著升高;雨季(2015年4月)时,施氮处理的土壤DOM含量升高,但其芳香性指数和腐殖化程度呈下降趋势。在增温和施氮的交互作用下DOM含量达到最高,其结构相对简单。除了温度和氮含量的直接影响外,RDA(冗余分析)表明,土壤含水量和pH也是决定土壤DOM变化的重要因子。增温和施氮均可以降低土壤pH,使得SOM更容易向DOM转化。增温会加速植物残体和SOM向DOM的溶解过程;施氮会通过促进植物生长,增加土壤DOM的含量。【Objective】As affected by anthropogenic activities,such as greenhouse agriculture that emits greenhouse gases,the global mean surface temperature rose by about 0.85℃ over the period of 1880-2012;and nitrogen deposition in China increased significantly by 0.41 kg·hm^–2 with each passing year over the period from 1980 to 2010.In the context of global warming,soil dissolved organic matter(DOM)attracts more and more attention due to its important role affecting global carbon and nitrogen balance,which is of great significance to the ecological environment.This study aims to investigate effects of soil warming and nitrogen addition on content and structure of soil DOM in the soil of Cunninghamia lanceolata plantations in subtropical China.【Method】In 2014-2015,a mesocosm field experiment was carried out in a Cunninghamia lanceolata plantations in subtropical China.The experiment was designed to have six treatments,that is,(1)CT(no warming and 0 kg·hm^–2·a^–1);(2)W(+5℃,0 kg·hm^–2·a^–1);(3)HN(no warming and 80 kg·hm^–2·a^–1);(4)LN(no warming and 40 kg·hm^–2·a^–1);(5)WHN(+5℃and 80 kg·hm^–2·a^–1);and(6)WLN,(+5℃and 40 kg·hm^–2·a^–1).Soil samples were collected in January 2015(dry season)and April 2015(rainy season),separately for analysis of DOM.【Result】Results show that soil warming increased the content of DOM,but decreased its aromaticity index and humification index,which might be attributed to the effect of high temperature promoting conversion of SOM(soil organic matter)into DOM.The impact of nitrogen addition on DOM structure showed a seasonal pattern.In the dry season,addition of nitrogen increased both the content and aromaticity index of DOM,while in the rainy season,it increased the content of DOM,but reduced its aromaticity and humification index significantly.Under the joint effect of high temperature and nitrogen addition,the DOM peaked in content and got simpler in structure.Besides the direct impacts of temperature and nitrogen content,soil moisture

关 键 词：增温 氮添加 杉木人工林 可溶性有机质 

分 类 号：S714[农业科学—林学]