Warming and elevated CO2 interactively affect the photosynthetic carbon of maize plant retained in major farming soils

Abstract

ABSTRACT Warming and elevated CO2 (eCO2) may influence the input of photosynthetic carbon (C) into soils and subsequent soil C storage. The biochemical properties vary among soils, which likely act different roles in the fate of photosynthetic C and soil C sequestration in response to warming and eCO2. However, the interactive effects of climate change and soil types on the photosynthetic C retained in soil and relevant mechanisms are poorly understood. We performed a pot experiment in open-top chambers to examine the effects of eCO2 (550 ppm) combined with elevated temperature (eT, 2 °C higher than the air temperature) on the retention of plant-C of maize (Zea mays L.) grown in Phaeozem, Fluvisol, Kastanozem and Acrisol with 13CO2 labeling at the silking stage. The proportion of 13C to the total fixed 13C increased by 44.6%, 96.1% and 41.9% in Phaeozem under eT, eCO2 and eT plus eCO2 treatments compared with control, while decreased in other three soils in response to either eCO2, eT or eT plus eCO2. The effect of climate change on fresh C input in maize cropping soils depended on soil type, and soil net C losses may occur in the Fluvisol, Kastanozem and Acrisol under climate change. Abbreviations: eCO2: elevated CO2, 550ppm; eT: warming; aCO2: ambient CO2, 400ppm; aT: ambient temperature; OTC: open-top chamber; DOC: dissolved organic carbon; SOC: soil organic carbon; C: carbon; S: soil; T: temperature.