Carbon flow in the plant-soil-microbe continuum at different growth stages of maize grown in a Mollisol

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.

KEYWORDS:

• ¹³CO₂ pulse labelling
• rhizodeposition
• maize
• soil organic carbon pools
• Mollisols

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The project was funded by the Key Project of Chinese Academy of Sciences: [Grant Number KZZD-EW-TZ-16-01], the National Natural Science Foundation of China: [Grant Number 41271261], and the Hundred Talents Program, Chinese Academy of Sciences.