Exchange fluxes of VOSCs between rice paddy fields and the atmosphere in the oasis <Emphasis Type="Bold">of arid area</Emphasis> in Xinjiang,China

Investigations about VOSCs (volatile organic sulfur compounds) have been received increasing attention for their significant contribution to the nonvolcanic background sulfate layer in the stratosphere and the earth’s radiation balance and as a potential tool to understand the carbon budget. In this study, COS and CS₂ were always recorded throughout the entire rice cultivation season of 2014. COS fluxes appeared as emission in non-planted soil and as uptake in planted soil, the corresponding results were obtained as 2.66 and ?2.35 pmol·m^?2·s^?1, respectively. For CS₂, both planted and non-planted paddy fields acted as sources with an emission rate of 1.02 pmol·m^?2·s^?1 and 2.40 pmol·m^?2·s^?1, respectively. COS emission or uptake rates showed a distinct seasonal variation, with the highest fluxes at the jointing-booting stage. COS and CS₂ fluxes increased with increasing N fertilizer use because of improved plant and microbial growth and activity. Plots treated with both N and S reduced COS and CS₂ fluxes slightly compared with plots with only-N treatment. Light, soil moisture or temperature showed no significant correlation with COS and CS₂ fluxes, but revealed the important impacts on the magnitude and direction of gases fluxes. The results also showed that the (available) sulfur contents in soil and roots had a certain effect on VOSCs emission or uptake. Our results highlight the significance of biotic and abiotic production and consumption processes existing in the soil.