Effects of precipitation on soil organic carbon fractions in three subtropical forests in southern China  

作　　者：Xiaomei Chen Deqiang Zhang Guohua Liang Qingyan Qiu Juxiu Liu Guoyi Zhou Shizhong Liu Guowei Chu Junhua Yan 

机构地区：[1]School of Geographical Sciences,Guangzhou University,Guangzhou 510006,China [2]South China Botanical Garden,Chinese Academy of Sciences,Guangzhou 510650,China [3]State Key Laboratory of Conservation and Utilization of Subtropical Agro-Bioresources,South China Agricultural University,Guangzhou 510650,China [4]University of Chinese Academy of Sciences,Beijing 100039,China

出　　处：《Journal of Plant Ecology》2016年第1期10-19,共10页植物生态学报（英文版）

基　　金：the Strategic Priority Research Program-Climate Change:Carbon Budget and Relevant Issues of the Chinese Academy of Sciences(XDA05050205);National Basic Research Program of China(2009CB421101);National Natural Science Foundation of China(NSFC-31400415);Guangdong Provincial Natural Science Foundation of China(8351065005000001),the Dinghushan Forest Ecosystem Research Station.

摘　　要：Aims The aim of this study was to investigate the effects of precipitation changes on soil organic carbon(SOC)fractions in subtropical forests where the precipitation pattern has been altered for decades.Methods We conducted field manipulations of precipitation,including ambient precipitation as a control(CK),double precipitation(DP)and no precipitation(NP),for 3 years in three forests with different stand ages(broadleaf forest[BF],mixed forest[MF]and pine forest[PF])in subtropical China.At the end of the experiment,soil samples were collected to assay SOC content,readily oxidizable organic carbon(ROC)and non-readily oxidizable organic carbon(NROC),as well as soil microbial biomass carbon(MBC),pH and total nitrogen content.Samples from the forest floors were also collected to analyze carbon(C)functional groups(i.e.alkyl C,aromatic C,O-alkyl C and carbonyl C).Furthermore,fine root biomass was measured periodically throughout the experiment.Important Findings Among the forests,ROC content did not exhibit any notable differences,while NROC content increased significantly with the stand age.This finding implied that the SOC accumulation observed in these forests resulted from the accumulation of NROC in the soil,a mechanism for SOC accumulation in the mature forests of southern China.Moreover,NP treatment led to significant reductions in both ROC and NROC content and therefore reduced the total SOC content in all of the studied forests.Such decreases may be due to the lower plant-derived C inputs(C quantity)and to the changes in SOC components(C quality)indicated by C functional groups analyses under NP treatment.DP treatment in all the forests also tended to decrease the SOC content,although the decreases were not statistically significant with the exception of SOC and ROC content in PF.This finding indicated that soils in MF and in BF may be more resistant to precipitation increases,possibly due to less water limitations under natural conditions in the two forests.Our results therefore highlight the different respo

关 键 词：rainfall pattern labile organic carbon soil organic carbon stable organic carbon forest floor 

分 类 号：S71[农业科学—林学]