『Abstract
　An outdoor pot experiments was conducted to investigate the effects of enhanced ultraviolet-B (UV-B) radiation on nitrous oxide (N2O) emissions from soil-winter wheat systems. The enhanced UV-B radiation treatments were simulated by 20％ increase in its intensity. N2O fluxes were measured with a static opaque chamber-gas chromatograph method. The results showed that enhanced UV-B radiation did not change the seasonal patterns of N2O emissions. Compared to the controls, the enhanced UV-B radiation reduced N2O fluxes by 16.4％ (p=0.015) during the elongation-booting stage, while it had no significant effects on N2O fluxes in the turning-green and heading-maturity phases. During the turning green-overall heading span, the accumulative N2O was largely decreased by the enhanced UV-B radiation (p＜0.05). From the overall heading to maturity, however, the effects of enhanced UV-B on N2O emissions were not pronounced (p＞0.10). At the elongation-booting stage, enhanced UV-B increased soluble proteins content in leaves, NO3^--N and NO4⁺-N content in rhizosphere soil, and soil microbial biomass C (Cmic) and N (Nmic; p＜0.05), as well as microbial biomass C:N ratio changing from 5.0 to 6.8. Our findings suggest that the effects of enhanced UV-B radiation on N2O emissions differed with winter wheat developmental stages. To assess the overall effects of enhanced UV-B radiation on N2O emissions from agroecosystems, nevertheless, more field measurements deserve to be carried out in various cropping systems.

Keywords: Enhanced UV-B radiation; N2O flux; Soil; Winter wheat』

1. Introduction
2. Materials and methods
　2.1. Site and soil description
　2.2. Pot experiments
　2.3. UV-B radiation
　2.4. Gas samples and measurements
　2.5. Plant and soil samples analysis
3. Results
　3.1. Seasonal change of N2O emissions
　3.2. Enhanced UV-B affected N2O emissions
　3.3. Enhanced UV-B affected crop properties
　3.4. Enhanced UV-B affected soil properties
4. Discussion
5. Conclusions
Acknowledgments
References