不同放牧退化阶段大针茅草原土壤有机碳稳定性及其来源研究  

Study on Stability and Source of Soil Organic Carbon in Stipagrandis Steppe at Different Grazing Degradation Stages

作　　者：任瑾涛 张璞进 吴英 朱蔚娜 金正亮 张艳丽 宝文智 清华 REN Jin-tao;ZHANG Pu-jin;WU Ying;ZHU Wei-na;JIN Zheng-liang;ZHANG Yan-li;BAO Wen-zhi;QING Hua(School of Ecology and Environment,Inner Mongolia University/Provinical and State Key Laboratory Breeding Base of Grassland Ecology/Key Laboratory of Mongolian Plateau Ecology and Resource Utilization of Ministry of Education,Inner Mongolia University,Hohhot 010021,China;Inner Mongolia Academy of Agricultural&Animal Husbandry Sciences,Hohhot 010031,China)

机构地区：[1]内蒙古大学生态与环境学院/省部共建草地生态学国家重点实验室培育基地/内蒙古大学蒙古高原生态学与资源利用教育部重点实验室,内蒙古呼和浩特010021 [2]内蒙古自治区农牧业科学院,内蒙古呼和浩特010031

出　　处：《中国草地学报》2021年第7期37-44,共8页Chinese Journal of Grassland

基　　金：国家自然科学基金项目(31560174,32060268,31960246);内蒙古自然科学基金项目(2018MS03072);内蒙古农牧业创新基金项目(2020CXJJM11)。

摘　　要：通过测定不同放牧退化阶段(轻度、中度和重度退化)大针茅典型草原的土壤总有机碳(TOC)、活性有机碳(LOC)和惰性有机碳(ROC)的含量,探究放牧退化过程中大针茅草原土壤总有机碳的组成及其稳定性。同时在群落调查的基础上,采用δ^(13)C稳定同位素技术阐明大针茅草原在放牧退化过程中群落组成变化对土壤总有机碳的影响。结果表明:(1)不同放牧退化阶段,TOC、LOC、ROC含量均随土层深度的增加而逐渐降低,且中度退化阶段TOC、LOC、ROC含量最高;(2)不同放牧退化阶段惰性碳指数值差异不显著,表明放牧未对大针茅群落土壤总有机碳的稳定性产生影响;(3)不同放牧退化阶段,大针茅草原土壤总有机碳主要来源于C_(3)植物。但是随着退化程度加剧,大针茅草原C_(3)植物的生物量降低,C_(4)植物的生物量增加,C_(4)植物对0~10cm土层土壤总有机碳的贡献增强。综上所述,以上结果可为综合评估长期放牧对大针茅草原土壤碳汇服务功能的影响,以及制定我国温室气体减排增汇策略提供科学依据。The contents of total organic carbon(TOC),labile organic carbon(LOC)and recalcitrant organic carbon(ROC)in soil of Stipa grandis steppe at different grazing degradation stages(light,moderate and severe conditions)were determined to explore the composition and stability of soil total organic carbon in the process of grazing degradation.Meanwhile,on the basis of plant community investigation,theδ13C stable isotope technology was used to elucidate the effects of plant community composition changes on soil total organic carbon in S.grandis steppe during grazing degradation.The results showed that(1)the contents of TOC,LOC and ROC gradually decreased with the increase of soil depth at different grazing degradation stages,and the contents of TOC,LOC and ROC were the highest at moderate degradation stage.(2)There was no significant difference in recalcitrance indices of carbon among different grazing degradation stages,indicating that the stability of soil organic carbon of S.grandis steppe was not influenced by grazing.(3)At different grazing degradation stages,the main source of soil organic carbon in S.grandis steppe was C_(3)plants.However,with the aggravation of degradation,the biomass of C_(3)plants decreased,the biomass of C_(4)plants increased,and the contribution of C_(4)plants to soil total organic carbon in 0~10 cm soil layer increased.In conclusion,this study provided scientific basis for comprehensive assessment of the impact of long-term grazing on soil carbon sink function of S.grandis steppe,as well as developing strategies for reducing greenhouse gas emission and increasing carbon sink in China.

关 键 词：大针茅草原 退化阶段 土壤总有机碳 惰性碳指数 δ^(13)C稳定同位素 

分 类 号：S812.2[农业科学—草业科学]