成土母质和土地利用方式对土壤有机碳化学组成的影响  

Effects of Parent Materials and Land Uses on Soil Organic Carbon Fractions

作　　者：覃智莲 杨孝民 宋照亮 邬思成 方小红[1] 彭渤[1] QIN Zhi-lian;YANG Xiao-min;SONG Zhao-liang;WU Si-cheng;FANG Xiao-hong;PENG Bo(Institute of Resouree and Fmironment Sciences,Hunan Normal Iniversily,Changsha 410081,China;Instiute of Suface-Earth System Science Research,Tianjin University,Tianjin 300072,China)

机构地区：[1]湖南师范大学资源与环境科学学院,湖南长沙410081 [2]天津大学表层地球系统科学研究院,天津300072

出　　处：《土壤通报》2020年第3期621-629,共9页Chinese Journal of Soil Science

基　　金：国家重点研究发展计划项目(2016YFA0601002和2017YFC0212703);国家自然科学基金项目(41930862和41571130042);湖南省地理学一流学科建设项目的共同资助。

摘　　要：土壤有机碳库是陆地生态系统中最重要的碳库之一,土地利用方式和成土母质是影响土壤总有机碳及其组分的重要因素。以湖南省花岗岩和玄武岩分布区的林地、旱地和稻田土壤(0~70 cm)为研究对象,采用H2SO4逐级水解法将土壤有机碳分为活性、半活性和惰性三个组分,探究土地利用方式和成土母质对土壤总有机碳及其各组分的影响。结果表明:不同母质和土地利用方式下,土壤活性、半活性、惰性有机碳含量随着土层深度的增加而逐渐降低,且与总有机碳含量均呈极显著正相关关系;土壤活性、半活性和惰性有机碳占总有机碳库的比例分别为31.38%~45.41%、3.68%~12.25%和40.83%~59.29%,且随土层深度的增加占比不发生显著变化;玄武岩地区,表层(0~20 cm)土壤活性、半活性、惰性以及总有机碳的储量在不同土地利用方式间占比不发生显著变化,而底层(20~70 cm)土壤活性、半活性、惰性以及总有机碳在稻田中的储量均显著高于林地;花岗岩地区,除表层土壤半活性有机碳以外,表层和底层土壤中总有机碳及各组分有机碳储量在不同土地利用方式间均无显著性差异。双因素方差分析表明,成土母质显著影响表层土壤总有机碳和惰性有机碳的储量,而土地利用方式则显著影响底层土壤活性、惰性以及总有机碳的储量。综上可见,土壤有机碳主要以惰性有机碳的形式存在,土地利用方式和成土母质对土壤有机碳及其组分剖面分布有不同的影响。Soil organic carbon(SOC)pool is one of the most important C pools in terrestrial ecosystems.The effects of land uses and parent materials on SOC and its fractions should not be ignored.Soil samples were collected from the profiles(0-70 cm)of forest land,upland,and paddy fields in the granite and basalt distribution regions in Hunan Province.The SOC fractions including labile organic C(LOC),semi-labile organic C(Semi-LOC)and recalcitrant organic C(ROC)were separated by using a modified H2 SO4 sequential hydrolysis method and the effects of land uses and parent materials on SOC and its fractions were investigated.The contents of LOC,Semi-LOC,and ROC generally decreased with increasing depth and were significantly correlated with the total SOC contents,respectively.The contributions of LOC,Semi-LOC,and ROC to total SOC pool were 31.38%-45.41%,3.68%-12.25%,and 40.83%-59.29%,respectively.The storages of LOC,Semi-LOC,ROC,and total SOC among different land uses were non-significant at the topsoil(0-20 cm)derived from basalt,while they were significantly higher in paddy field than in forest land at the subsoil(20-70 cm).Except for the storage of Semi-LOC in topsoil(0-20 cm),the storages of SOC and its fractions at the topsoil(0-20 cm)and subsoil(20-70 cm)developed from granite were non-significant among different land uses.The storages of LOC,ROC,and SOC at the topsoil(0-20 cm)were significantly affected by parent materials,while those at the subsoil(20-70 cm)were mainly controlled by land uses.The above results indicated that ROC is the largest component of SOC pool;the effects of land uses and parent materials on SOC and its fractions were different between the topsoil and subsoil in the studied regions.

关 键 词：土地利用方式 成土母质 活性有机碳 半活性有机碳 惰性有机碳 

分 类 号：P595[天文地球—地球化学]