极端降雨事件对不同类型生物土壤结皮覆盖土壤碳释放的影响

Effects of Extreme Rainfall Events on the Carbon Release of Biological Soil Crusts and the Covered Soil in Fixed Sand Dunes in the Tengger Desert,Northern China

于2011年5—8月,选择腾格里沙漠东南缘人工固沙植被区藻类、藓类和混生结皮覆盖的土壤为对象,研究了极端降雨量(降雨量44.7mm、强度0.04mm.min-1)、极端降雨强度(降雨量8.3mm、强度0.55mm.min-1)及普通降雨(降雨量16.3mm、强度0.02mm.min-1)条件下的碳释放过程。碳释放量的测定采用Li-6400-09土壤呼吸室,降雨结束后立即开始观测,直到呼吸速率恢复到降雨前水平时停止观测。结果表明:极端降雨(降雨量和降雨强度)结束初期藻类和混生结皮覆盖土壤的呼吸速率受到明显抑制,藻类结皮覆盖土壤呼吸速率分别为0.12μmol.m-2.s-1和0.41μmol.m-2.s-1,混生结皮覆盖土壤呼吸速率分别为0.10μmol.m-2.s-1和0.45μmol.m-2.s-1;而极端降雨对藓类结皮覆盖土壤的影响不明显,呼吸速率分别为0.83μmol.m-2.s-1和1.69μmol.m-2.s-1。这说明处于演替高级阶段的藓类结皮能够很好地应对短期的极端降雨事件。

In May to August of 2011, the effects of natural extreme rainfall events on the carbon release of different types of Biological Soil Crusts （BSC） and the covered soil were measured in fixed sand dunes in the Tengger Desert, Northern China. An Li-6400-09 Soil Chamber was used to measure the respiration rate of the BSCs and the soil immediately after the rainfall stopped, until the respiration rate went close to the prerainfall basal rate. The results showed that the respiration rate of the algal crust and mixed crust were significantly restrained by extreme precipitation events in the initial stage after extreme rainfall events （extreme precipitation events and extreme rainfall intensity events）, however, moss crust was not significantly influenced. The respiration rates of algal crust, mixed crust and moss crust in extreme precipitation events and extreme rainfall intensity events were 0.12 and 0.41μmol·m^-2·S^-1 , 0.10μmol·m^-2·S^-1 and 0.45μmol·m^-2·S^-1, 0. 83 μmol·m^-2·S^-1 and 1.69μmol·m^-2·S^-1 , respectively. Our study indicated that moss crust in advanced succession stage can adapt to extreme precipitation events better in a short period.