Properties of dissolved organic matter related to soil organic matter quality and nitrogen additions in Norway spruce forest floors
Properties of dissolved organic matter related to soil organic matter quality and nitrogen additions in Norway spruce forest floors
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DOI：
10.1016/j.geoderma.2005.01.023
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发表时间：
2006-02
期刊：
影响因子：
6.1
通讯作者：
K. Michel;E. Matzner;M. Dignac;I. Kögel‐Knabner
中科院分区：
文献类型：
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作者：
K. Michel;E. Matzner;M. Dignac;I. Kögel‐Knabner
溶解有机质(DOM)的质量是高度可变的，关于DOM质量与其母质土壤有机质(SOM)的结构和组成之间的关系的信息很少。增加对森林土壤的氮素输入对土壤有机质和DOM的结构和组成的影响在很大程度上还不清楚。本文研究了15株北欧和中欧挪威云杉(Picea abies(L.)喀斯特。)站着。Oa材料在15°C和持水能力下进行有氧培养10个月，并用人工穿透雨溶液每月提取一次。每周测定一次土壤呼吸。选取8个试验点，研究了矿质氮输入对土壤DOM组成和呼吸速率的影响。未处理的Oa样品中溶解有机碳的释放量为0.0~5 8.6μg C day−1g C−1，且随C/N比的增加而增加。DOM的1HIX和UV吸收与木质素衍生化合物的氧化程度呈负相关，与SOM的C/N比呈正相关，而与SOM的芳香C含量呈正相关。矿质氮的添加对呼吸速率没有显著影响。在8个样品中，有6个样品的N处理引起了比紫外线吸收的增加或DOM的1倍。然而，这些影响在统计上并不显著。添加矿质氮不影响DOM的释放速率。结果表明，土壤有机质的性质在很大程度上决定了森林枯枝落叶层中DOM的数量和质量。矿质氮的添加可能会改变DOM的质量，但我们不能确定DOM释放的显著变化。
The quality of dissolved organic matter (DOM) is highly variable and little information is available on the relation of DOM quality to the structure and composition of its parent soil organic matter (SOM). The effect of increasing N inputs to forest soils on the structure and composition of both SOM and DOM also remains largely unclear. Here we studied the release of DOM, its specific UV absorption and two humification indices (HIX) derived from fluorescence spectra from Oa material of 15 North- and Central-European Norway spruce (Picea abies (L.) Karst.) stands. The Oa material was incubated aerobically at 15 °C and water holding capacity over a period of 10 months and extracted monthly with an artificial throughfall solution. Soil respiration was determined weekly. The influence of mineral N inputs on composition of DOM and on respiration rates was investigated on periodically NH4NO3-treated Oa samples of eight selected sites. Release of dissolved organic carbon (DOC) from untreated Oa material samples ranged from 0.0 to 58.6 μg C day−1g C−1and increased with increasing C-to-N ratio. One HIX and UV absorption of DOM were negatively correlated to the degree of oxidation of lignin-derived compounds and positively to the C-to-N ratio and – HIX only – to the aromatic C content of SOM. Mineral N addition had no distinct effect on respiration rates. In six of eight samples the N-treatment caused an increase in specific UV absorption or one HIX of DOM. However, these effects were not statistically significant. Addition of mineral N did not affect the rates of DOM release. Our results show that properties of SOM largely determine the amount and quality of DOM in forest floors. Changes of DOM quality due to mineral N additions are likely, but we cannot confirm significant changes of DOM release.