Elevated Atmospheric CO₂ in Relation to Farmland Carbon Cycling

Soil is the largest carbon (C) pool in terrestrial ecosystems.Elevated atmospheric CO₂ (eCO₂) influences the stability of this C pool via the plant-soil-microbe interaction.Many plant species exhibit significant increase of growth in response to eCO₂,which is likely to alter organic carbon input to the soil.The community structure and function of soil microorganisms may also change under eCO₂ and probably have substantial influence on carbon cycling in terrestrial ecosystems as these microorganisms are subjected to be involved in the transformation of soil carbon.This paper summarized the effect of eCO₂ on soil carbon cycle,which included the root growth of crops in response to eCO₂,and quantitative and qualitative alternations on the photosynthates input to the soil under eCO₂.The feedback mechanisms of soil carbon pool in response to eCO₂ were also addressed in the perspective of soil microorganisms.It is proposed that the soil microbial community should be further investigated in order to better understand the relationship between soil carbon and atmospheric CO₂.Thus,the mechanism of soil microorganisms being involved in the turnover of soil organ carbon is essential to clarify the pattern of carbon cycling in arable soils under global climate change.