高寒地区生态修复草地和林地土壤颗粒有机碳分解特征  

Soil particle organic carbon isotope decomposition characteristics of ecological restoration grassland and woodland in alpine region

作　　者：汉光昭 曹广超[1,2,4] 曹生奎 冶文倩[1,2,3] Han Guangzhao;Cao Guangchao;Cao Shengkui;Ye Wenqian(Key Laboratory of Ministry of Education of Earth Surface Process and Ecosystem Conservation in Qinghai-Tibet Plateau,Qinghai Normal University,Xining 810008,China;Qinghai Provincial Key Laboratory of Physical Geography and Environment Process,Qinghai Normal University,Xining 810008,China;School of Geographical Sciences,Qinghai Normal University,Xining 810008,China;Academy of Plateau Science and Sustainability(APSS),People's Government of Qinghai Province&Beijing Normal University,Xining 810008,China)

机构地区：[1]青海师范大学青藏高原地表过程与生态保育教育部重点实验室,青海西宁810008 [2]青海师范大学青海省自然地理与环境过程重点实验室,青海西宁810008 [3]青海师范大学地理科学学院,青海西宁810008 [4]青海省人民政府-北京师范大学高原与可持续发展研究院,青海西宁810008

出　　处：《中国沙漠》2022年第5期36-43,共8页Journal of Desert Research

基　　金：国家重点研发计划项目(2017YFC0404304);青海省科技厅重大专项(2019-SF-A12);青海省自然科学基金项目(2018-ZJ-903);青海省创新平台建设专项青海省自然地理与环境过程重点实验室项目(2020-ZJ-Y06)。

摘　　要：为探讨高寒地区生态修复用地土壤颗粒有机碳(POC)分解特征,以祁连山南坡的修复草地和修复林地为研究对象,使用离心法将土壤分为砂粒(2000-50μm)、粉粒(2-50μm)和黏粒(<2μm),对土壤颗粒有机碳含量、土壤颗粒有机碳分配及颗粒有机碳稳定同位素组成特征进行了研究。结果表明:(1)两种修复用地均能提高颗粒有机碳的含量,新增的颗粒有机碳在修复草地中以砂粒有机碳为主体,在修复林地以粉粒和黏粒有机碳为主体。(2)3种土壤颗粒δC值均随粒径变小而增大,δC值与颗粒有机碳含量对数的回归斜率随着粒径变小而降低,修复林地叶片与表土有机碳的δ13C值分馏幅度高于修复草地,根系与表土有机碳的δC值分馏幅度小于修复草地。(3)修复草地砂粒、粉粒、黏粒有机碳平均周转时间分为9、20、34 a,修复林地分别为20、29、94 a,且两种修复用地的3种颗粒有机碳周转时间均有随修复年限增加而变长趋势。两种生态修复用地土壤颗粒有机碳的分解程度和周转速率均随着粒径减小而增大,从叶片转换为黏粒有机碳的过程中,修复林地周转速率较大,从根系转换成黏粒有机碳的过程中,修复草地更快。In order to investigate the decomposition characteristics of soil particulate organic carbon in alpine ecological restoration land,the restoration grassland and woodland on the southern slope of Qilian Mountain were studied in this study. The soil was divided into sand(2 000-50 μm),silt(2-50 μm)and clay(<2 μm)using centrifugation,and the content of soil particulate organic carbon(POC),distribution of soil POC and stable isotopic composition(δC)of POC were analyzed. The results showed that both types of restoration land could increase the content of POC,sand organic carbon was the main part of the newly increased POC in the restoration grassland,and silt and clay organic carbon was the main part in the restoration woodland. With the decrease of soil particle size,the δC values increased gradually,the regression slope(K)of δC value and LOG(POC)decreased with decreasing particle size. The fractionation range of δC value of leaf and topsoil in restoration woodland was higher than that in restoration grassland,while the fractionation range of δC value of root and topsoil organic carbon was lower than that in restoration grassland. The average turnover time of sand,silt and clay organic carbon in the restored grassland was 9 a,20 and 34 a,and that in the restored forest land was 20 a,29 a and 94 a,respectively. The turnover time of three kinds of particulate organic carbon in the two restoration lands increased with the increase of restoration years. In conclusion,the decomposition degree and turnover rate of soil POC increased with the decrease of particle size. In the process of conversion from leaves to clay organic carbon,the turnover rate of restored forest was faster,and in the process of conversion from root to clay organic carbon,the restoration of grassland was faster.

关 键 词：有机碳同位素 生态修复 颗粒有机碳周转 

分 类 号：S153[农业科学—土壤学]