| 摘要: |
| 【目的】研究黄土高原水蚀风蚀交错带几种常见树种凋落物（枯落叶及植物残体）中各种形态氮素的含量及其关系，为进一步评价其在植物 土壤氮素转化中的作用提供依据。【方法】以中科院水土保持研究所神木水蚀风蚀交错带生态环境检测站周围山坡上的8种常见树种（乔木类刺槐和小叶杨，灌木类沙柳和沙棘，草本植物沙打旺、长芒草、白羊草和紫花苜蓿）凋落物为研究对象，测定其可溶性全氮（TSN）、可溶性有机氮（SON）和游离氨基酸（FAA）的含量，并分析它们之间的关系。【结果】供试8种树种凋落物TSN含量占全氮（TN）的比例为5.00%～29.07%；不同植物凋落物的SON含量为0.32～6.24 g/kg，占TSN的比例为35.56%～83.32%；沙打旺和紫花苜蓿凋落物中TSN和SON的含量较高，与其他植物凋落物的差异大多达显著水平。相关分析表明，8种植物凋落物中TSN、SON、无机氮和全氮之间的相关性达极显著水平。【结论】8种常见植物凋落物中的可溶性氮，特别是可溶性有机氮是凋落物中不可忽视的氮素形态。 |
| 关键词: 黄土水蚀风蚀交错带 植物凋落物 可溶性有机氮 游离氨基酸 |
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| 基金项目:国家“十一五”科技支撑计划项目（2007BAD89B02）；国家自然科学基金项目(40571087)；西北农林科技大学拔尖人才支持计划项目（2006） |
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| Contents of different nitrogen forms in main plant residues in water wind erosion crisscross region of the Loess Plateau |
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| Abstract: |
| 【Objective】Contents of different nitrogen forms in various main plant residues were quantified to evaluate their effects on N cycling in plant soil in water wind erosion crisscross region of the Loess Plateau of China.【Method】Eight tree species and plant residues were collected from hillsides of Shenmu Monitoring Platform,the Institute of Soil and Water Conservation,Chinese Academy of Sciences,to determine the concentrations of total soluble nitrogen (TSN),soluble organic nitrogen (SON) and free amino acids (FAA) in these residues.And the relationships between different nitrogen forms were also studied.【Result】TN comprised 5.00% to 29.07% of TSN in eight tree species and plant residues.The means of soluble organic carbon ranged from 0.32 to 6.24 g/kg,which comprised 35.56% to 83.32% of TSN.Additionally,concentrations of TSN and SON both in the erect milkvetch（Astragalus adsurgens Pall）and the alfalfa（Medicago sativa L.）were significantly higher than that in most of other plant residues.Correlation analysis showed that there were significant differences between TSN,SON,inorganic N and TN in eight plant residues.【Conclusion】It is concluded that the soluble nitrogen,especially soluble organic nitrogen is an important pool of N in the plant residues. |
| Key words: water wind erosion crisscrosses region of the Loess Plateau plant residue soluble organic nitrogen free amino acid |
