川西锦鸡儿灌木扩张对高寒草地土壤有机碳矿化的影响  

Effects of Caragana erinacea shrub expansion on soil organic carbon mineralization in alpine grassland

作　　者：黎萱 耿行 高永恒[2] 陈东毅 李良安 王平[1] LI Xuan;GENG Hang;GAO Yongheng;CHEN Dongyi;LI Liangan;WANG Ping(Resources and Environment College of Gansu Agricultural University,Lanzhou 730070,China;Chengdu Institute of Biology,Chinese Academy of Sciences,Chengdu 610041,China;Energy Bureau of Qianxinan Buyi and Miao Autonomous Prefecture,Guizhou Province,Xingyi 562400,China)

机构地区：[1]甘肃农业大学资源与环境学院,兰州730070 [2]中国科学院成都生物研究所,成都610041 [3]贵州省黔西南布依族苗族自治州能源局,兴义562400

出　　处：《生态学报》2024年第16期7150-7159,共10页Acta Ecologica Sinica

基　　金：国家自然科学基金(32371649);四川省重点研发计划项目(2022YFS0489)。

摘　　要：以川西锦鸡儿(Caragana erinacea)灌丛草地为研究对象,分析川西锦鸡儿灌木不同扩张程度下(原生草地、中度灌木扩张和重度灌木扩张)0—10 cm、10—20 cm和20—40 cm土壤理化性质及土壤有机碳(SOC)矿化的变化特征,探究灌木扩张对高寒草地SOC矿化的影响机制。结果表明:(1)灌木扩张对土壤全氮(TN)含量无显著影响,显著增加各土层SOC含量,显著增加10—20 cm土壤矿物矿质结合态有机碳(MAOC)含量及其占SOC比例,显著减小0—20 cm土壤含水量(SWC)。重度灌木扩张显著增加10—40 cm土壤微生物生物量碳(MBC)含量,显著减小0—10 cm土层MBC/SOC和MAOC/SOC。(2)不同土壤深度对SOC矿化激发效应存在差异,灌木扩张显著降低0—10 cm土壤有机碳潜在矿化碳库(C_(0)),重度灌木扩张显著增加10—40 cm土层C_(0)。(3)相关性分析表明,SOC矿化过程与SWC、SOC、TN、MBC和MAOC显著正相关,与MAOC/SOC显著负相关。逐步回归分析表明,SOC矿化与MBC和SWC相关性最强,可以有效解释C_(0)变化的91.1%。由此推断,川西锦鸡儿灌木扩张后该区域SOC矿化的变化,主要是由于灌木扩张影响MBC和SWC所致,土壤浅表水分减少影响微生物活动使得SOC矿化减弱,灌木根系发育土层微生物量增多使得SOC矿化增强。In this paper,Caragana erinacea shrub grassland in western Sichuan was taken as the research object.The changes of soil physical and chemical properties and soil organic carbon(SOC)mineralization in 0—10 cm,10—20 cm and 20—40 cm under different expansion degrees of Caragana erinacea shrub(native grassland,moderate shrub expansion,and heavy shrub expansion)were analyzed,and the influence mechanism of shrub expansion on SOC mineralization in alpine grassland was explored.The results showed that:(1)Shrub expansion had no significant effect on soil total nitrogen(TN)content,significantly increased SOC content in each soil layer,significantly increased mineral mineral-associated organic carbon(MAOC)content and its proportion in SOC in 10—20 cm soil,and significantly decreased soil water content(SWC)in 0—20 cm soil.In the stage of heavy shrub expansion,the content of microbial biomass carbon(MBC)in 10—40 cm soil layer was significantly increased,and MBC/SOC and MAOC/SOC in 0—10 cm soil layer were significantly decreased.(2)Shrub expansion significantly reduced the potential mineralized carbon pool(C_(0))of soil organic carbon in 0—10 cm soil layer,and the C_(0) in 10—40 cm soil layer was significantly increased in the expansion stage of heavy shrubs.(3)Correlation analysis showed that SOC mineralization process was significantly positively correlated with SWC,SOC,TN,MBC and MAOC,and significantly negatively correlated with MAOC/SOC.Stepwise regression analysis showed that the SOC mineralization had the strongest correlation with MBC and SWC,which could effectively explain 91.1%of the change of C_(0).It can be inferred that the change of SOC mineralization in this area after Caragana erinacea shrub expansion is mainly due to the influence of shrub expansion on MBC and SWC.The decrease of soil superficial water affects microbial activity and weakens SOC mineralization,while the increase of microbial biomass in shrub root development layer strengthens SOC mineralization.

关 键 词：土壤有机碳矿化 灌木扩张 高寒草地 川西锦鸡儿 

分 类 号：S812.2[农业科学—草业科学]