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作 者 ：安宗胜,詹婧,孙庆业*

期 刊 ：生态学报 2010年 30卷 21期 页码：5958~5966

关键词：无机氮；有机氮；铜尾矿；生态恢复；植物群落；

Keywords:inorganic nitrogen, organic nitrogen, copper mine tailing, ecological restoration, plant communities,

摘 要 ：为探讨自然生态恢复过程中铜尾矿废弃地氮素各组分的变化，采集铜尾矿废弃地不同植物群落下的表尾矿样品经室内自然风干、研磨、过筛，用2mol/L KCl提取后进行无机氮各组分含量分析，有机氮各组分含量分析采用Bremner法。结果表明，样品中总氮含量为40.9-1366.1mg/kg，其中总无机氮含量为1.7-8.8mg/kg，占总氮的0.5%-4.3%；酸解氮含量为20.8-361.4mg/kg，占总氮的20.3%-51.9%；酸未解氮含量为20.1-1004.7mg/kg，占总氮的48.1%-79.7%。不同植物群落下尾矿中无机氮、有机氮各组分含量存在较大差异。在无机氮中，铵态氮、硝态氮和亚硝态氮含量为1.7-3.0mg/kg、未检出-58mg/kg和0.019-0.038mg/kg，所占总氮比例为0.2%-4.2%、0-1.8% 和0.003%-0.057%。随着生态系统从裸地→隐花植物结皮→维管植物群落发展，表层尾矿中总无机氮含量逐渐增加，表现为尾矿裸地 < 隐花植物结皮 < 维管植物群落；但对维管植物群落而言，随着植物群落发育时间的增加，表层尾矿中无机氮占总氮的比例逐渐降低。数据分析表明：处于演替初期的裸地、隐花植物结皮生长处的尾矿中铵态氮为有效态氮的主要存在形式，而维管植物群落下尾矿中硝态氮为有效氮的主要形态，占无机氮总量60.0%以上。随着植物群落从裸地、隐花植物结皮向维管植物群落的发展，以及维管植物群落发育时间的延长，表层尾矿中酸解氮和酸未解氮含量逐渐积累。在酸解氮中，氨基酸氮、氨态氮、氨基糖态氮和未知氮含量变化范围分别为4.7-95.7mg/kg、5.8-37.3mg/kg、8.2-38.8mg/kg和2.1-194.6mg/kg，占总氮比例分别为7.2%-11.9%、2.8%-14.1%、2.5%-20.1%和3.4%-19.7%。除杨山冲裸地外，有机氮以酸未解氮为主，同时随着尾矿废弃地弃置时间的延长及植物群落的演替，酸未解氮所占总氮比例有所提高，酸解氮所占比例则呈递减趋势。目前尾矿中有机质和总氮含量仍处于较低的水平，养分的形成、积累尚处于初期阶段，尾矿中氮素的积累过程主要表现为有机氮（尤其是酸未解氮）的积累过程。

Abstract:The changes of nitrogen components in wastelands of copper mine tailings were investigated with the samples collected from the copper mine tailings under different plant communities after natural drying, grinding and sieving in indoor. The inorganic nitrogen content of these samples was determined after extraction using 2mol/L KCl, whereas organic nitrogen content was measured by Bremner approach. The results showed that the total nitrogen (TN) content was 40.9-1366.1mg/kg in which total inorganic nitrogen content was 1.7-8.8mg/kg, accounting for TN of 0.5%-43%; acidic hydrolysable nitrogen content was 20.8-361.4mg/kg, accounting for TN of 20.3%-51.9%; acidic unhydrolysable nitrogen content was 20.1-1004.7mg/kg, accounting for TN of 48.1%-79.7%. A remarkable difference was observed in the inorganic and organic nitrogen contents among the samples. In the inorganic nitrogen components, the content ranges were 1.7-3.0mg/kg for ammonium nitrogen, undetectable-5.8mg/kg for nitrate nitrogen and 0.019-0.038mg/kg for nitrite nitrogen, which respectively occupied 0.2%-4.2%, 0-1.8% and 0003%-0.057% of TN. The contents of inorganic nitrogen components in the upper layer of copper mine tailings gradually increased as the eco-system development from bare lands→cryptogamic crusts→vascular plant communities, and followed the order of bare lands < cryptogamic crusts < vascular plant communities. But in terms of vascular plant communities, the percentage of total inorganic nitrogen in TN in the upper layer of copper mine tailings decreased with the increase of plant community development time. Data analysis showed that in the early successional bare lands and cryptogamic crusts, ammonium nitrogen mainly exists as a main form of available nitrogen, whereas the nitrate nitrogen is the main form of available nitrogen in the tailings under vascular plant communities, occupying above 60.0% for total inorganic nitrogen. The acidic hydrolysable nitrogen and acidic unhydrolysable nitrogen accumulated gradually with the succession of plant communities and the increase of vascular plant community development time. In the acidic hydrolysable organic nitrogen components, the content ranges were 4.7-95.7 mg/kg for amino acid nitrogen, 5.8-37.3mg/kg for ammoniacal nitrogen, 8.2-38.8mg/kg for aminosugar nitrogen and 2.1-194.6mg/kg for unknown nitrogen, which respectively occupied 7.2%-11.9%, 2.8%-14.1%, 25%-20.1% and 3.4%-19.7% of TN. The percentage of acidic unhydrolysable nitrogen, as the main parts of organic nitrogen in addition to the samples from Yangshanchong bare land, in TN increased simultaneously with the succession of plant communities and the extension of the disposed time of copper mine tailing, but an contrary trend was displayed in the percentage of acidic hydrolysable nitrogen in TN. At present, organic matter and TN content in the wastelands of copper mine tailings are still at a low level and the formation and accumulation of nutrients in the wastelands of copper mine tailings are still in its early stages. The accumulation process of organic nitrogen (in particular, acidic unhydrolysable nitrogen) is the main accumulations of nitrogen in copper mine tailings.

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