土壤呼吸是陆地生态系统通过根系呼吸和微生物呼吸向大气中释放CO2的过程。研究土壤呼吸的时空格局,将有助于构建区域尺度土壤呼吸定量评价模型,也可提高预测未来气候变化情境下的典型生态系统、区域以及全球尺度碳平衡状况的能力。本文整合了中国区域土壤呼吸的主要研究成果,分析了温度敏感性(Q10)和土壤呼吸(Rs)的统计特征和区域差异,定量评价了中国区域Rs的时空格局及其在中国和全球碳平衡中的作用。通过以上分析本文得出以下主要结论：①不同生态系统类型的土壤呼吸的Q10表现为森林>农田>草地,气候越寒冷,土壤呼吸Q10越大,并且中国区域的Q10值相对于其他国家偏低;②Rs具有明显的季节变异,不同生态系统类型的Rs表现为森林>农田>草地,并且,中国区域Rs低于全球Rs;③月尺度上Rs随着经纬度发生明显的季节变异,随着经度的增加,Rs的季节变幅也逐渐增加;④1995-2004 年中国区域Rs的年总量的平均值为3.84 PgC,占全球土壤CO2排放的比例4.78%。
Soil respiration is a major process of carbon dioxide emission from terrestrial ecosystems to atmosphere. Researches on spatiotemporal patterns of soil respiration could be helpful to the construction of a quantitative evaluation model of soil respiration at regional scale, and also, could improve our predictive ability of carbon balance status under future climate change of typical ecosystems at regional or global scale. This paper integrated the main research results about the soil respiration at regional scale in China, analyzed the statistical characteristics and regional difference of temperature sensitivity and soil respiration, and in addition, the quantitative evaluation on the spatiotemporal distribution and its effects on the carbon balance at China’s even global scale was also given in this paper. The results showed that Q10 of forest ecosystem was the highest, followed by that of farmland ecosystem, and Q10 of grassland ecosystem was lowest, indicating that Q10 was higher while air temperature was lower. Also, Q10 of terrestrial ecosystem in China was lower than that of other countries. Rs displayed a significant seasonal variation. Rs of different ecosystems presented a similar changing trend with Q10. There was seasonal dynamics of monthly Rs along latitude and longitude gradients. Additionally, the seasonal amplitude of Rs increased with increasing longitude. Between 1995 and 2004, the Rs in China, with an average value of 3.84 Pg C·a-1, contributed 4.87% to the global soil CO2 emission.
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