模拟增温和不同氮素添加对三江源区高寒草甸草地生产力影响初步探究

Preliminary investigation for the effects of the simulated warming and the addition of different nitrogen on grassland productivity of alpine meadow in the Three- river headwater region

为了研究高寒草甸草地植被对模拟增温和不同氮素添加的响应机制,试验在野外条件下对三江源区高寒草甸进行模拟增温和铵态氮、硝态氮的氮素添加,进行植物群落结构调查,检测物种丰富度、多样性指数、植物种群重要值。结果表明:增温施铵态氮、增温施硝态氮处理的植被高度显著高于对照(P<0.05),盖度无显著差异(P>0.05);生物量增温施铵态氮、增温施硝态氮处理显著高于增温不施氮处理和对照(P<0.05),并且从高度和优良牧草生物量来看增温施铵态氮、增温施硝态氮处理均高于其他处理,但高度增温施硝态氮>增温施铵态氮,生物量增温施铵态氮>增温施硝态氮,增温施铵态氮处理优势种重要值比较高,增温不施氮处理能增加群落丰富度指数、均匀度指数和多样性指数,且阻碍了土壤水分含量的增加,增温施铵态氮处理的土壤水分含量相对较高。说明增温和施铵态氮互作更有利于植物的生长。

To study the response mechanism of the alpine meadow vegetation to the simulated warming and the addition of different nitrogen,the simulated warming and nitrogen addition with ammonium and nitrate nitrogen were performed in the alpine meadow from the Three- river headwater region under field conditions. The investigation of plant community structure was conducted,and then the species richness,diversity index,and the important values of plant populations were also detected. The results showed that the height of vegetation in the treatments with the application of ammonium nitrogen with warming and the application of nitrate nitrogen with warming was significantly higher（ P〈0. 05） than that of the control treatment,but the coverage had no significant difference（ P〈0. 05）; the biomass in the treatments with the application of ammonium nitrogen with warming and the application of nitrate nitrogen with warming was significantly higher（ P〈0. 05） than that in the treatments of warming without the nitrogen application and the control treatment; seen from the height and biomass of fine herbage,the treatments with the application of ammonium nitrogen with warming and the application of nitrate nitrogen with warming were higher than other treatments,but the height in the treatment of the application of nitrate nitrogen with warming was higher than that in the treatment of the application of ammonium nitrogen with warming,and the biomass in the treatment of the application of ammonium nitrogen with warming was higher than that in the treatment of the application of nitrate nitrogen with warming. The important values of dominant species were high in the treatment of the application of ammonium nitrogen with warming,and the treatment of warming without the nitrogen application could increase the community richness index,evenness and diversity indexes,and hindered the increase of soil water content. The soil water content in the treatment of the application of ammonium nitrogen with warming was relatively high. The results indicate that the interaction of warming with the application of ammonium nitrogen is more conducive to the growth of plants.