中文摘要：

采用随机区组设计,探讨了不同施肥时期及氮肥用量对三江源区高寒草甸初级生产力、植物养分及土壤养分的影响。结果表明：在施肥时间为7月10日,施肥量为150kg·hm-2时,地上生物量为最大值,较对照增加了2.06倍（P〈0.05）。而植物氮素含量在施肥时间为7月10日,尿素用量为300kg·hm-2时达到最大值,较对照增加了31.18%（P〈0.05）。相关性分析表明,地上生物量与植物全氮成显著正相关,施氮量与植物全氮成线性相关。施肥时间为7月10日左右时,尿素施用水平为150～300 kg·hm-2,该类型高寒草甸初级生产力和土壤全氮都达到最大值,可作为优先氮素添加量来推荐。

英文摘要：

The effects of different fertilizer application time and amount on biomass,plant nutrients,and soil nutrients were studied using random block design in Alpine meadow in the Three-River Source Region.The results showed that aboveground biomass reached maximum under the application amount of 150 kg·hm~（-2） and application time of 10~（th） July,increased by 2.06 times than CK（P0.05）.Compared with CK,the plant nitrogen increased by31.18%（P0.05） under the application amount of 300 kg·hm-2 and application time of 10~（th） July.Correlation analysis showed that plant total nitrogen was significantly positive correlated with aboveground biomass.There were positive correlation between nitrogen fertilizer and plant total nitrogen.Above findings suggested that primary productivity and soil total nitrogen values were maximum when fertilizer amount was from 150 kg·hm-2 to 300kg·hm-2 and fertilizer time was 10th July.