Abstract: This study investigated the distribution and utilization of different forms of nitrogen in alpine meadows, in order to provide a theoretical basis for adaptive management of nitrogen in alpine meadows. This study was conducted in alpine meadows in chenduo County, Yushu Prefecture. Four treatments were used to determine the total nitrogen and nitrogen recovery in plants and soils under different forms of nitrogen addition, including blank control (N0), ammonium nitrogen (N1, (¹⁵NH₄)₂SO₄), nitrate nitrogen (N2, Ca(¹⁵NO₃)₂) and amide nitrogen (N3, CO(¹⁵NH₂)₂). The results showed that the addition of different forms of nitrogen had significant impacts on the above-ground biomass and total nitrogen content of plants (P<0.05), but had no significant impact on soil total nitrogen content. The nitrogen utilization of current season ranged from 6.28% to 26.82%, the residual rate in soil ranged from 16.06% to 58.13%, and the loss rate ranged from 15.05% to 77.66%. The experiment showed that the amide nitrogen in alpine meadows is the best form for increasing plant above-ground biomass, total nitrogen content and nitrogen utilisation.

Key words: Isotope labelling, Alpine meadow, Nitrogen form, Nitrogen partitioning

摘要： 为了探究不同形态氮素在高寒草甸中的分配及利用情况，本研究以玉树州称多县的高寒草甸为研究对象，利用¹⁵N标记技术，设置对照（N0）、铵态氮（N1，（¹⁵NH₄）₂SO₄）、硝态氮（N2，Ca （¹⁵NO₃）₂）、酰胺态氮（N3，CO （¹⁵NH₂）₂）四种处理，测定不同形态氮素添加下植物和土壤中的全氮及氮素回收率的指标。结果表明：不同形态氮素添加对植物地上部分生物量及全氮含量影响显著（P<0.05），但对土壤全氮含量无显著影响；氮素的当季利用率在6.28%～26.82%之间，土壤残留率在16.06%～58.13%之间，损失率在15.05%～77.66%之间。试验表明高寒草甸中酰胺态是提高植物地上生物量、全氮含量及氮素利用率的最佳氮素形态。

关键词: 同位素标记, 高寒草甸, 氮素形态, 氮素分配