Subtropical giant podzol chronosequence reveals that soil carbon stabilisation is not governed by litter quality
Subtropical giant podzol chronosequence reveals that soil carbon stabilisation is not governed by litter quality
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DOI：
10.1007/s10533-015-0093-4
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发表时间：
2015-05-01
期刊：
影响因子：
4
通讯作者：
Schmidt, Susanne
中科院分区：
文献类型：
--
作者：
Jones, Andrew R.;Sanderman, Jonathan;Schmidt, Susanne
土壤和大气之间碳通量的大小促使人们努力更好地理解对植物凋落物中碳的命运的控制，这些碳以二氧化碳的形式重新进入大气或以土壤有机碳（SOC）的形式被隔离。它仍然没有得到解决，如果长期的命运是由凋落物的生物化学特性或土壤特性，降低了土壤生物体分解凋落物衍生的碳的能力。活性土壤矿物质在稳定SOC中发挥的突出作用阻碍了对凋落物质量对SOC长期稳定性的单一作用的调查。在这里，我们调查了凋落物质量对土壤碳稳定性的独立影响，跨越460，000年的沙丘时间序列，其特征在于显著的营养和凋落物质量梯度，干扰土壤矿物质的存在最少。使用稳态营业额模型来解释放射性碳活性的土壤中收集的每千份40年分开，我们发现，营业时间的SOC在A层平均为22年（范围从16至27年）的年代序列。这一发现强烈对比其他时序，SOC周转率范围从60至726年，与变化丰富的土壤矿物质和组成。我们的研究表明，SOC在表层的长期稳定性可能在很大程度上取决于与土壤矿物质的相互作用，凋落物质量本身并不支配碳稳定。
The magnitude of the carbon flux between soil and atmosphere has prompted efforts to better understand the controls over the fate of carbon in plant litter that re-enters the atmosphere as carbon dioxide or is sequestered as soil organic carbon (SOC). It remains unresolved if the long-term fate of litter carbon is driven by biochemical properties of litter or by soil properties that reduce the ability of soil organisms to decompose litter-derived carbon. The prominent role that reactive soil minerals play in stabilising SOC have hindered investigation into the single role of litter quality on long-term SOC stability. Here we investigated the independent effects of litter quality on soil carbon stabilisation across a 460,000 year sand dune chronosequence characterised by a pronounced nutrient and litter quality gradient with minimum presence of interfering soil minerals. Using a steady state turnover model to interpret radiocarbon activity in soils collected a parts per thousand 40 years apart, we show that the turnover time of SOC in the A horizon averaged 22 years (ranging from 16 to 27 years) across the chronosequence. This finding strongly contrasts other chronosequences where SOC turnover rates range from 60 to 726 years in concert with changing abundance and composition of soil minerals. Our study demonstrates that the long-term stability of SOC in surface horizons may be largely determined by interaction with soil minerals and that litter quality per se does not govern carbon stabilisation.