Bias of SOC dynamics study deduced from isotopic fractionation in corn
Carbon stable isotope techniques were extensively employed to trace the dynamics of soil organic carbon(SOC),especially during the land-use change involving in a shift of vegetation with different photosynthetic pathways.Based on the isotopic mass balance equation,the relative contributions of new vs.old SOC and SOC turnover rate in corn field were evaluated around world-wide.However,most of researches ignored the investigation on corn debris left in field,and simply put an average δ13C value of corn plant or a measured value of a part into formula to calculate proportion of corn-derived SOC,which could bring bias on their results.This paper carried out an exquisite analysis of the isotopic fractionation in corn plant and deduced the possible max bias of SOC dynamics study.The results show there is approximate 3‰ isotopic fractionation from top to bottom corn leaf.13C enrichment sequence in corn plant is tassel>stalk or cob>root>leaves.Each part that accounts for the total dry mass of corn is different greatly.Consequently,the average δ13C value of corn cant represent the actual isotope composition of corn debris.Furthermore,this paper deduced that greater the fractionation in corn plant,greater the possible bias.Finally,to alleviate bias of SOC dynamics study,the paper put forward two measures.First is to analyze isotope composition and proportion of each part of corn.Second is to investigate and make sure which parts of corn plant are left in field and incorporated into SOC.
Bias of SOC dynamics study isotopic fractionation in corn isotope mass balance equation bias range
Chenglong Tu Congqiang Liu Xiaohui Lu Lifeng Cui Jiayin Du
State Key Laboratory of Environmental Geochemistry,Institute of Geochemistry,Chinese Academy of Scie Guizhou Normal University,Guiyang 550001,China
国际会议
The 11th International Symposium on Geochemistry of the Earths Surface(GES-11)(第十一届地球表层地球化学国际研讨会)
贵阳
英文
1-4
2017-06-11（万方平台首次上网日期，不代表论文的发表时间）