Substrate quality and the temperature sensitivity of soil organic matter decomposition
Substrate quality and the temperature sensitivity of soil organic matter decomposition
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DOI：
10.1016/j.soilbio.2008.01.007
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发表时间：
2008-07-01
影响因子：
9.7
通讯作者：
Ineson, Phil
中科院分区：
文献类型：
--
作者：
Hartley, Iain P.;Ineson, Phil
确定不同土壤有机质库分解的相对温度敏感性对于预测气候变化对土壤碳储量的长期影响至关重要。虽然动力学理论表明SOM分解的温度敏感性应该随着底物的顽固性而增加，但很少有经验证据支持这一假设。在这里提出的研究中，从单个散装土壤样品中提取的子样品被冷冻并依次解冻，以产生孵育不同时间（最多124天）的同一土壤样品。然后将这些样品放入孵化系统中，该系统可以持续监测CO(2)的产生，并研究土壤呼吸对短期温度操作的响应。随着培养时间的延长，土壤CO(2)产生的温度敏感性显著增加，表明随着最稳定的SOM池的耗尽，SOM分解的温度敏感性增加。因此，本研究是第一个为动力学理论提供实证支持的研究之一。此外，使用建模方法，我们证明了更顽固的SOM池分解的温度敏感性将决定长期的土壤c损失。因此，在以前的模拟研究中，对全球变暖的正反馈的幅度可能被低估了。(c) 2008 Elsevier Ltd.版权所有。
Determining the relative temperature sensitivities of the decomposition of the different soil organic matter (SOM) pools is critical for predicting the long-term impacts of climate change on soil carbon (C) storage. Although kinetic theory suggests that the temperature sensitivity of SOM decomposition should increase with substrate recalcitrance, there remains little empirical evidence to support this hypothesis. In the study presented here, sub-samples from a single bulk soil sample were frozen and sequentially defrosted to produce samples of the same soil that had been incubated for different lengths of time, up to a maximum of 124 days. These samples were then placed into an incubation system which allowed CO(2) production to be monitored constantly and the response of soil respiration to short-term temperature manipulations to be investigated. The temperature sensitivity of soil CO(2) production increased significantly with incubation time suggesting that, as the most labile SOM pool was depleted the temperature sensitivity of SOM decomposition increased. This study is therefore one of the first to provide empirical support for kinetic theory. Further, using a modelling approach, we demonstrate that it is the temperature sensitivity of the decomposition of the more recalcitrant SOM pools that will determine long-term soil-C losses. Therefore, the magnitude of the positive feedback to global warming may have been underestimated in previous modelling studies. (c) 2008 Elsevier Ltd. All rights reserved.