短期围封和放牧条件下施氮对橐吾型退化草地植被的影响

Effects of Nitrogen Addition on Vegetation of Ligularia sibirica Degraded Grassland under Short-Term Enclosure and Grazing Conditions

氮素是植物体内各种物质的重要组成部分,添加氮素能促进植物生长,提高牧草生产力。为研究短期氮素添加对黄帚橐吾(Ligularia virgaurea)型退化草地群落多样性及草地生产力的影响,本研究在黄帚橐吾严重危害草地的自由放牧区和围封区进行氮素添加处理,分析了2年内物种重要值、植物多样性、黄帚橐吾密度以及植物地上、地下生物量的变化规律。结果表明:添加氮素后禾本科植物重要值明显升高,短期围封和氮素添加对黄帚橐吾型退化草地的多样性无显著影响;围封条件下添加氮素对禾本科地上生物量、总地下生物量以及0~10 cm地下生物量影响显著(P<0.05);处理和年份之间无明显交互作用。通过主成分综合得分得到在放牧草地添加氮素可以有效提高草地得分,该结果可为黄帚橐吾型退化草地的治理恢复提供一定理论依据。

Nitrogen is an important component of various substances in plants.Nitrogen addition can promote plant growth and improve forage productivity.In order to study the effects of short-term nitrogen addition on community diversity and grassland productivity of Ligularia virgaurea degraded grassland,the nitrogen addition treatment was carried out in the free grazing area and enclosure area of L.virgaurea seriously endangering grassland in this study.The changes of species importance value,vegetation diversity,density of L.virgaurea and aboveground and underground biomass of plants in two years were analyzed.The results showed that the important values of Graminae increased significantly after nitrogen addition.Short-term enclosure and nitrogen addition had no significant effect on the diversity of the degraded grassland.Enclosure with nitrogen addition had a significant effect on the aboveground biomass of Gramineae,total underground biomass and the underground biomass of 0~10 cm soil layer(P<0.05).There was no significant interaction between treatments and years.According to the comprehensive score of principal component,nitrogen addition on the free grazing grassland could effectively enhance the score of grassland.The results could provide a theoretical basis for the management and restoration of L.virgaurea degraded grassland.