THE TEMPERATURE-DEPENDENCE OF SOIL ORGANIC-MATTER DECOMPOSITION, AND THE EFFECT OF GLOBAL WARMING ON SOIL ORGANIC-C STORAGE
THE TEMPERATURE-DEPENDENCE OF SOIL ORGANIC-MATTER DECOMPOSITION, AND THE EFFECT OF GLOBAL WARMING ON SOIL ORGANIC-C STORAGE
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DOI：
10.1016/0038-0717(94)00242-s
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发表时间：
1995-06-01
影响因子：
9.7
通讯作者：
KIRSCHBAUM, MUF
中科院分区：
文献类型：
--
作者：
KIRSCHBAUM, MUF
气候变化研究中的一个关键问题涉及目前储存在土壤有机质中的大量C的未来动态。随着全球变暖，这个碳池中的碳量会增加还是减少？未来土壤有机碳含量的变化趋势将取决于净初级生产力和土壤有机质分解速率的相对温度敏感性。净初级生产力的温度依赖性方程已被广泛使用，但分解速率的温度依赖性不太清楚。文献进行了调查，以获得不同研究中报道的土壤呼吸和N动态的温度依赖性。只有实验室为基础的测量，以避免混杂效应与凋落物投入率，凋落物质量，土壤湿度或其他环境因素的差异。已经报道了相当大范围的值，在低温下观察到分解过程对温度的最大相对敏感性。与文献数据拟合的关系表明，在0 ℃下，分解速率随温度增加而增加，Q（10）几乎为8。有机物分解的温度敏感性随温度升高而降低，Q（10）随温度降低，在10 ℃时约为4.5，在20 ℃时约为2.5。在低温下，分解的温度敏感性比净初级生产力的温度敏感性大得多，而温度敏感性在较高的温度下变得更加相似。分解的温度敏感性比净初级生产力高得多，对土壤有机碳在土壤中的储存有重要意义。这些数据表明，温度升高1摄氏度可能最终导致世界上年平均温度为5摄氏度的地区土壤有机碳损失超过10%，而同样的温度升高将导致30摄氏度土壤有机碳损失仅3%。这些差异在绝对量上甚至更大，因为较冷的土壤含有更大量的土壤有机碳。这一分析支持了以往研究的结论，即土壤有机碳含量可能会随着全球变暖而大幅下降，从而在全球碳循环中提供正反馈。
One of the key questions in climate change research relates to the future dynamics of the large amount of C that is currently stored in soil organic matter. Will the amount of C in this pool increase or decrease with global warming? The future trend in amounts of soil organic C will depend on the relative temperature sensitivities of net primary productivity and soil organic matter decomposition rate. Equations for the temperature dependence of net primary productivity have been widely used, but the temperature dependence of decomposition rate is less clear. The literature was surveyed to obtain the temperature dependencies of soil respiration and N dynamics reported in different studies. Only laboratory-based measurements were used to avoid confounding effects with differences in litter input rates, litter quality, soil moisture or other environmental factors. A considerable range of values has been reported, with the greatest relative sensitivity of decomposition processes to temperature having been observed at low temperatures. A relationship fitted to the literature data indicated that the rate of decomposition increases with temperature at 0 degrees C with a Q(10) of almost 8. The temperature sensitivity of organic matter decomposition decreases with increasing temperature, indicated by the Q(10) decreasing with temperature to be about 4.5 at 10 degrees C and 2.5 at 20 degrees C. At low temperatures, the temperature sensitivity of decomposition was consequently much greater than the temperature sensitivity of net primary productivity, whereas the temperature sensitivities became more similar at higher temperatures. The much higher temperature sensitivity of decomposition than for net primary productivity has important implications for the store of soil organic C in the soil. The data suggest that a 1 degrees C increase in temperature could ultimately lead to a loss of over 10% of soil organic C in regions of the world with an annual mean temperature of 5 degrees C, whereas the same temperature increase would lead to a loss of only 3% of soil organic C for a soil at 30 degrees C. These differences are even greater in absolute amounts as cooler soils contain greater amounts of soil organic C. This analysis supports the conclusion of previous studies which indicated that soil organic C contents may decrease greatly with global warming and thereby provide a positive feed-back in the global C cycle.