%0 Journal Article %T Rhizosphere Effects of Maize on Inorganic and Organic Carbon Release in Calcareous Soils %A SUN,Zhaoan %A ZHAO,Yi %A ZHU,Biao %A CHEN,Qing %A CAO,Hui %A HE,Minyi %A MENG,Fanqiao %J ACTA PEDOLOGICA SINICA %@ 0564-3929 %V 58 %N 4 %D 2021 %P 998-1007 %K Rhizosphere effects;Three-source partitioning of soil CO2;Decomposition of soil organic carbon;Dissolution of soil inorganic carbon;Root-derived respiration %X [Objective] In calcareous soil, CO2in rhizosphere soil comes from at least three sources, i.e., respiration of roots, decomposition of soil organic C (SOC) and dissolution of soil inorganic C (SIC). Owing to technical limitations in partitioning CO2 by source, how rhizosphere effects affect SOC decomposition and SIC dissolution is still an issue not yet clarified. Therefore, an in-lab pot experiment using calcareous soil collected from a farmland of North China to grow maize in an attempt to investigate rhizosphere effects of summer maize plants on release of CO2 from SOC and SIC, using the IsoSource model to partition CO2 in the rhizosphere by source.[Method] At the end of the elongation (24-53 days), heading (54-66 days) and grain-filling (67-99 days) stages of the summer maize, destructive sampling of maize rhizospheres was carried out separately for analysis of content of 13C from root, SOC and SIC, separately. During the period from the beginning of the elongation stage to the end of the maize growth stage, soil respiration and 13C content in the soil with or without maize planted was monitored at a three-day interval with the aid of the IsoSource software.[Result] Results show that to the total soil CO2 emission, root respiration contributed 48.0%, SOC did 31.2% and SIC did 20.8%. During the period from the elongation stage to the end of the summer maize season, CO2 emission from SOC and from SIC in the pot with maize planted was 65% and 156% higher than their respective ones in the pot without maize planted.[Conclusion] This experiment indicates that SIC plays a significant role in stabilizing global C pool and regulating atmospheric CO2 concentration. If the contribution of SIC to soil CO2 emission in calcareous soils is ignored, the amount of CO2from SOC decomposition may be overestimated, which will inevitably affect quantification of the priming effects of SOC. This study will help reduce uncertainties in of soil C budgeting for farmlands of calcareous soil in North China. %R 10.11766/trxb201911210581 %U http://pedologica.issas.ac.cn/trxben/home %1 JIS Version 3.0.0