13C abundance, water-soluble and microbial biomass carbon as potential indicators of soil organic carbon dynamics in subtropical forests at different successional stages and subject to different nitrogen loads
13C abundance, water-soluble and microbial biomass carbon as potential indicators of soil organic carbon dynamics in subtropical forests at different successional stages and subject to different nitrogen loads
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DOI：
10.1007/s11104-009-9890-7
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发表时间：
2009-07-01
期刊：
影响因子：
4.9
通讯作者：
Li, Shenggong
中科院分区：
文献类型：
--
作者：
Fang, Hua-Jun;Yu, Gui-Rui;Li, Shenggong
长期大气氮沉降影响森林生态系统碳氮循环，从而改变植物和土壤碳同位素丰度。研究了干扰林、恢复林和成熟林3个演替阶段对不同氮素输入水平的响应。在低、中、高氮水平下进行了氮素调控试验。为了研究碳循环对氮添加的响应，测定了叶片、枯落物和土壤的C浓度和C-13天然丰度。通过测定矿质土壤中活性有机碳组分来定量分析土壤有机碳的动态变化。结果表明，连续3年施氮对富氮林叶片C、N含量无显著影响，但降低了C/N比，富集了C-13。此外，施氮显著降低了富氮林表层土壤微生物量碳，增加了水溶性有机碳。本研究表明，N添加增强了单位C同化的优势植物物种的耗水量，限制SOC周转在N-贫林在早期和中期的演替阶段（从而有利于SOC封存），反之亦然，N丰富的成熟森林。
Chronic atmospheric nitrogen deposition affects the cycling of carbon (C) and nitrogen (N) in forest ecosystems, and thereby alters the stable C isotopic abundance of plant and soil. Three successional stages, disturbed, rehabilitated and mature forests were studied for their responses to different nitrogen input levels. N-addition manipulative experiments were conducted at low, medium and high N levels. To study the responses of C cycling to N addition, the C concentration and C-13 natural abundances for leaf, litter and soil were measured. Labile organic carbon fractions in mineral soils were measured to quantify the dynamics of soil organic C (SOC). Results showed that three-year continuous N addition did not significantly increase foliar C and N concentration, but decreased C/N ratio and enriched C-13 in N-rich forests. In addition, N addition significantly decreased microbial biomass C, and increased water soluble organic C in surface soils of N-rich forests. This study suggests that N addition enhances the water consumption per unit C assimilation of dominant plant species, restricts SOC turnover in N-poor forests at early and medium successional stages (thus favored SOC sequestration), and vice versa for N-rich mature forests.