增温对亚热带森林土壤可浸提有机碳的影响  

Effects of soil warming on water extractable organic carbon in subtropical forest

作　　者：白皓宇 杨智杰[1] 郑永[1] 熊德成[1] 周嘉聪 BAI Hao-yu;YANG Zhi-jie;ZHENG Yong;XIONG De-cheng;ZHOU Jia-cong(College of Geograph-ical Science,Fujian Normal University,State Key Laboratory of Subtropical Mountain Ecology(Funded by Ministry of Science and Technology and Fujian Province),Fujian Normal University,Fuzhou 350007,China)

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

出　　处：《生态学杂志》2020年第5期1436-1444,共9页Chinese Journal of Ecology

基　　金：国家重点基础研究发展计划(2014CB954003)资助。

摘　　要：土壤可浸提有机碳(WEOC)在森林碳循环中起到重要作用,对气候变化有着高度的敏感性。本研究利用土壤增温(+5℃)技术,通过3种不同浸提方式研究增温对亚热带森林土壤可浸提有机碳的影响。结果表明:增温并没有改变不同土壤深度冷水(CWEOC)与盐浸提(SWEOC)的WEOC浓度,但增温减少了0~10 cm土层的热水浸提可浸提有机碳(HWEOC)的浓度(-51.2%),而增加了10~20、20~40和40~60 cm土层的HWEOC浓度,分别增加67.1%、781.7%和501.6%。与对照相比,增温分别增加了20~40和40~60 cm土层的微生物生物量碳(MBC)98.2%和163.1%,但对0~10和10~20 cm土层MBC没有影响。不同方法浸提的WEOC浓度存在显著差异,总体上以CWEOC浓度最低,HWEOC和SWEOC分别在土壤表层与底层最高。因此,在气候变暖条件下,增温促进根系向深层土壤生长,提高深层土壤根系碳输入和微生物活性,从而导致土壤WEOC的变化。同时,不同浸提方法的结合,可以更有效反映土壤中WEOC的来源与变化。本研究结果为深入了解亚热带土壤碳循环对气候变化的响应机制提供依据。Water extractable organic carbon(WEOC)is sensitive to climate change,and thus plays a vital role in carbon cycling in forest ecosystems.Here,the effects of soil warming(+5℃)on soil WEOC extracted by three different methods were examined in a subtropical forest.Concentrations of WEOC extracted by cold water(CWEOC)and salt solution(SWEOC)were not affected by soil warming.Soil warming reduced the concentration of WEOC extracted by hot water(HWEOC)by 51.2%at the 0-10 cm soil layer,but elevated HWEOCby 67.1%,781.7%,and 501.6%,respectively,at the 10-20,20-40 and 40-60 cm soil layer.Soil warming increased microbial biomass carbon(MBC)by 98.2%and 163.1%at the 20-40 and 40-60 cm soil later,respectively,but had no effect on MBC at the 0-10 and 10-20 cm.There was a significant difference in soil WEOC concentrations extracted by the three different methods.Generally,the concentration of CWEOC was the lowest among the three extraction methods,and HWEOCand SWEOC were the highest in surface soil layer and deep layer,respectively.The significant effect of soil warming on WEOC could be ascribed to warming-stimulated deeper rooting,which enhance root carbon input and microbial activity in the subsoil and thus induce a decrease of WEOC in the topsoil and an increase of WEOC in the subsoil.Different extraction methods could be used together to reflect different origins and transformations of WEOC.These results could facilitate our understanding of the responses of soil carbon cycling to climate change in subtropical forests.

关 键 词：土壤可浸提有机碳 土壤增温 亚热带 杉木 

分 类 号：S714.2[农业科学—林学]