氮硅添加对高寒草甸波伐早熟禾的影响

以青藏高原东缘植物群落常见种波伐早熟禾（Poa poophagorum）为例，研究了不同水平的氮肥、硅肥添加对其多度、地上生物量和叶片全氮含量的影响。结果表明，单独添加氮肥时，随着氮肥浓度的增加，其多度、地上生物量和叶片全氮含量均表现出上升的趋势；单独添加硅肥时，随着硅肥添加浓度的增大，其多度、地上生物量和叶片全氮含量呈现先增大后不变的趋势，其峰值均出现在中浓度硅肥处理（8 g·m^-2）下。氮、硅配施下其地上生物量、多度和叶片全氮含量均存在显著的交互作用，其地上生物量、多度和叶片全氮含量均出现先增加后不变的趋势，且峰值出现在硅肥为8 g·m^-2处。在青藏高原东缘高寒草甸施氮肥时，添加硅肥有利于提高群落中波伐早熟禾的多度、地上生物量和叶片全氮含量，氮肥添加量以90 g·m^-2，硅肥添加量以8 g·m^-2最适宜。

Effect of Nitrogen and Silicon Addition on Poa Poophagorum in Alpine Meadow

Poa poophagorum is the common species in the Qinghai-Tibet Plateau. In this study,it was taken as an object to study the changes in abundance,aboveground biomass,and leaf nitrogen content under different levels of nitrogen and silicon fertilizers. The results showed that when nitrogen fertilizer was added alone,its abundance,aboveground biomass and leaf total nitrogen content all showed an upward trend with the increase of nitrogen fertilizer concentration. While silicon fertilizer was added separately,the abundance,aboveground biomass,and leaf nitrogen content of plant showed a trend of increasing first and then remaining unchanged as its concentration increased,and the peak value appeared at the middle concentration (8 g·m^-2). In addition,there were significant interactions between above-ground biomass,abundance and total nitrogen content of leaf under the combined fertilization of nitrogen and silicon,which showed a trend of increasing first and then remaining unchanged and the peak appeared at the place where the silicon fertilizer was 8 g·m^-2. These results indicated that when nitrogen fertilizer was applied on the eastern edge of the Tibetan Plateau,the appropriate addition of silicon fertilizer can increase the abundance,above-ground biomass,and leaf total nitrogen content of Poa poophagorum Bor, the common species of plant communities in alpine meadow. The most suitable amount for nitrogen fertilizer was 90 g·m^-2 and silicon fertilizer was 8 g·m^-2.