摘要:荒漠土壤温室气体排放是陆地碳氮循环的重要组成部分，目前人工建植促进植被恢复对非生长季荒漠土壤CH₄、N₂O通量的影响尚不明确。本研究采用静态暗箱-气相色谱和时空替代法，分析非生长季库布齐沙漠东部不同植被恢复阶段土壤CH₄、N₂O通量特征及其与环境因子之间的关系，探讨植被恢复对非生长季荒漠土壤温室气体排放的影响。结果表明：非生长季荒漠土壤是CH₄的吸收汇，也是N₂O的排放源。不同植被恢复阶段CH₄平均吸收量和N₂O排放量均表现为：苔藓结皮固定沙地（47.6 μg CH₄ m^-2 h^-1，13.5 μg N₂O m^-2 h^-1） > 地衣结皮固定沙地（32.2 μg CH₄ m^-2 h^-1，9.1 μg N₂O m^-2 h^-1） > 藻结皮固定沙地（23.7 μg CH₄ m^-2 h^-1，8.7 μg N₂O m^-2 h^-1） > 半固定沙地（22.4 μg CH₄ m^-2 h^-1，5.0 μg N₂O m^-2 h^-1） > 流动沙地（18.7 μg CH₄ m^-2 h^-1，3.9 μg N₂O m^-2 h^-1）。荒漠土壤在不同冻结时期温室气体排放存在较大差异，融冻期CH₄吸收贡献率最大，在结冻期N₂O排放贡献率最大。非生长季荒漠土壤存在明显的水热同期现象，土壤水热因子对N₂O通量的影响较小，仅半固定沙地土壤温度与N₂O通量呈显著正相关；而在藻类、地衣和苔藓结皮固定沙地中，土壤温度和含水量均与CH₄通量呈显著负相关。植被恢复过程中，生物量的积累和土壤理化性质的改善，能够显著影响荒漠土壤CH₄、N₂O通量的变化。因此，人工建植促进植被恢复实现沙漠化逆转可改变荒漠生态系统的温室气体排放格局。



Abstract:Greenhouse gas emission from desert soil is an important part of terrestrial carbon and nitrogen cycle, while the influence of artificial vegetation restoration on CH₄ and N₂O fluxes in desert soil in non-growing seasons is still not clear. In this paper, the static chamber and gas chromatography technique were used. We performed a spatial series analysis that represented at emporalseries to study the desert soil CH₄ and N₂O fluxes corresponding to the different stages of vegetation restoration during non-growing season. We also explored the correlation of these fluxes with the environmental factors and studied the effects of revegetation on desert soil CH₄ and N₂O fluxes in the eastern Hobq Desert, China. The results showed that the desert soil was a sink of CH₄ and a contributor to N₂O emission during non-growing season. The change trend for CH₄ and N₂O fluxes at different restoration stages were the same:moss crust fixed sand (47.6 μg CH₄ m^-2 h^-1, 13.5 μgN₂O m^-2 h^-1) > lichen crust fixed sand (32.2 μg CH₄ m^-2 h^-1, 9.1 μg N₂O m^-2 h^-1 > algae crust fixed sand (23.7 μg CH₄ m^-2 h^-1, 8.7 μg N₂O m^-2 h^-1) > semi-fixed sand (22.4 μg CH₄ m^-2 h^-1, 5.0 μg N₂O m^-2 h^-1) > mobile dune (18.7 μg CH₄ m^-2 h^-1, 3.9 μg N₂O m^-2 h^-1). The greenhouse gas emissions of desert soil in different freezing periods were significantly different. The CH₄ absorption contribution rate was the largest in thawing period, while the N₂O emission contribution rate was the largest in freezing period. During the non-growing season, there was an obvious hydrothermal synchronization in desert soil. The soil hydrothermal factors had little effect on the N₂O flux. Only the soil temperature in semi-fixed sandy land had a significant positive correlation with the N₂O flux. But in algae, lichen and moss crust fixed sands, soil temperature and moisture content were all negatively correlated with the CH₄ flux. In the process of vegetation restoration, the accumulation of biomass and the improvement of soil physical and chemical properties could significantly affect the changes of CH₄ and N₂O fluxes in desert soil. Therefore, the artificial vegetation restoration and desertification reversal could alter the pattern of greenhouse gas emissions in desert ecosystem.





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