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季节性雪被是高寒森林冬季土壤呼吸的重要调控因子,气候变化导致的季节性雪被减少可能对高寒森林冬季土壤呼吸产生显著影响。该研究采用人工去除雪被的方法,研究雪被去除对川西亚高山云杉(Picea asperata)人工林冬季土壤呼吸的影响。结果表明:与对照相比,雪被去除加大了土壤温度波动,使冬季土壤表层和5 cm平均温度分别降低了1.12和0.34℃,冻融循环次数分别增加了39和12次;冬季平均土壤呼吸速率和土壤碳排放通量分别为0.52μmol·m~(–2)·s~(–1)和88.44 g·m~(–2),雪被去除使冬季平均土壤呼吸速率和碳排放通量分别降低了21.02%和25.99%,雪被效应主要发生在雪被初期;冬季土壤呼吸与土壤温度存在显著的指数关系,雪被去除显著降低了冬季土壤呼吸温度敏感性。未来气候变化所引发的季节性雪被减少可能会降低川西亚高山森林冬季土壤碳排放,从而对亚高山森林土壤碳动态产生深远影响。
Seasonal snow is an important regulator of winter soil respiration in the alpine forest. The reduction of seasonal snow caused by climate change may have a significant impact on winter soil respiration in the alpine forest. In this study, artificial snow removal was used to study the effects of snow removal on winter soil respiration in Picea asperata plantations in western Sichuan. The results showed that compared with the control, the removal of snow increased the temperature fluctuation of soil, which decreased 1.12 and 0.34 ℃ in surface layer and average temperature of 5 cm in winter and 39 and 12 times in freezing and thawing cycles respectively. In winter, The respiration rate and soil carbon flux were 0.52 μmol · m -2 · s -1 and 88.44 g · m -2, respectively. The removal of snow caused the average soil respiration rate and carbon flux in winter The amount of snow was reduced by 21.02% and 25.99% respectively. The effect of snow was mainly occurred in the early stage of snowfall. In winter, there was a significant exponential relationship between soil respiration and soil temperature. Snow removal significantly reduced the winter soil respiration temperature sensitivity. The reduction of seasonal snow caused by future climate change may reduce winter soil carbon emission in sub-alpine forests in western Sichuan, and thus have a far-reaching impact on soil carbon dynamics in subalpine forests.