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.
Disclosure statement
No potential conflict of interest was reported by the authors.