UV-B辐射增强对小麦秸秆化学成分及其施用后土壤N2O排放的影响

在室外试验的基础上，研究了地表UV-B辐射增强条件下小麦秸秆成分的变化，及在室内不同培养条件下施用UV-B辐射处理后小麦秸秆对土壤N₂O排放的影响.室外试验结果表明：地表UV-B辐射增强减少了小麦地上部分生物量，显著增加了小麦秸秆木质素和全氮含量，增幅分别达94.2%和12.3%，降低了其C/N.室内培养试验结果表明：与常规小麦秸秆相比，UV-B辐射处理后的小麦秸秆显著提高了旱地和淹水条件下N₂O的排放量；施用秸秆同时伴施硝态氮条件下，经过UV-B辐射处理的小麦秸秆显著促进了旱地条件下N₂O的排放，其排放量为常规秸秆处理的3.2倍，但在淹水条件下对N₂O排放无显著影响；无论何种培养条件下，经过UV-B辐射处理的小麦秸秆对土壤呼吸都未产生显著影响.

Effects of elevated ultraviolet-B radiation on the chemical composition of wheat straw and the N2O emission from soil amended with the straw

An outdoor experiment was carried out to investigate the effects of elevated ultraviolet-B radiation on the chemical composition of wheat straw, and an indoor incubation test was conducted to study the effects of the amendment of the straw on soil N₂O emission.Outdoor experiment showed that the enhanced UV-B decreased the aboveground biomass of wheat, increased the lignin and total N contents of wheat straw by 94.2% and 12.3%, respectively, and decreased the C/N ratio of the straw. Incubation test showed that comparing with the amendment of conventional wheat straw, the amendment of wheat straw received enhanced UV-B radiation during plant growth increased soil N₂O emission under the dry-land and flooded conditions significantly. When nitrate was applied, the soil N₂O emission in the treatment withstraw received enhanced UV-B radiation during plant growth was 3.2 times higher than that with the conventional straw under dry-land condition, but did not differ significantly under flooded condition. The amendment of wheat straw which received UV-B radiation during plant growth had no significant effects on soil respiration.