Carbon flow in the plant-soil-microbe continuum at different growth stages of maize grown in a Mollisol |
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| Authors: | Zhenhua Yu Yansheng Li Xiaobing Liu Guanghua Wang |
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| Institution: | Key Laboratory of Mollisols Agroecology, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Harbin, China |
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| Abstract: | Understanding the photosynthetic carbon (C) dynamics in the plant–soil–microbe continuum is critical to the C sequestration in soils. However, such information is limited in maize (Zea mays L.) in Mollisols. Pot-grown maize was labelled with 13CO2 at the 10-leaf, 15-leaf, heading, milk and dent stages to investigate the photosynthetic C flow in a maize–soil system and its contribution to soil organic carbon (SOC) in Mollisols. The majority of fixed 13C was recovered in shoots, ranging from 44.7% to 78.6%. The allocation of 13C fixed at different growth stages to belowground (roots and soil) gradually decreased over the growing period, indicating that the strength of root C sink is stronger at the early stages. However, the proportion of 13C in dissolved organic C and microbial biomass C to that in SOC significantly increased as the growth stages advanced. Over the entire growth period, the contribution of root-derived C to SOC was estimated to be 5461 mg C plant?1 growth period?1, of which approximately 79% was synthesized during the vegetative stages. Therefore, the input of photosynthetic C by maize plants into SOC mainly occurred during the younger stages of the plant, favouring the storage of SOC in Mollisols. |
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| Keywords: | 13CO2 pulse labelling rhizodeposition maize soil organic carbon pools Mollisols |
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