土壤藻结皮对退化草地土壤肥力和植物群落多样性的影响

Effects of Soil Algal Crust on Soil Fertility and Plant Community Diversity in Degenerated Grassland

为探究土壤藻结皮对退化草地生态恢复的影响,在库布齐沙漠南缘退化草地,分别应用常规分析方法、样方调查法以及物种的多样性指数、丰富度指数和均匀度指数,研究人工土壤藻结皮发育过程中土壤肥力、植物群落结构和物种多样性的变化。结果表明:经过3年的土壤藻改良,50 cm埋深的土壤中,土壤含水率增加了19.9%~123.9%,土壤中有机质含量增加了20.0%~30.4%,土壤中全氮和速效氮含量分别增加了31.6%~33.3%和22.8%~52.9%,土壤中全磷和速效磷含量分别增加了13.1%~20.3%和41.2%~53.7%;随着土壤藻结皮的发育,研究区退化草地增加了沙蓬、羊柴、沙柳和柠条4种草本植物,植物群落物种的多样性指数、丰富度指数和均匀度指数分别增加了67.0%、82.4%和57.9%,退化草地植物生产量由58.5 g DW/m2增加到241.6 g DW/m2,说明随着土壤藻结皮的发育,退化草地的土壤环境条件得到改善,植物群落结构和物种多样性明显增强,表明培植土壤藻结皮将有利于改善土壤环境,加速退化草地的生态恢复。

In order to explore the influence of soil algal crust on the ecological restoration of degenerated grassland, this study investigates the soil fertility, plant community structure and species diversity using conventional analysis methods, quadrat survey method, species diversity index, richness index and evenness index during the artificial algal crust development in the southern margin of the Hobq Desert.The results show that both soil moisture content and soil fertility have a marked increase after 3-year soil algal improvement.The soil moisture content, organic matter content, total nitrogen, available nitrogen, total phosphorus and available phosphorus increased by 19.9%~123.9%,20.0%~30.4%,31.6%~33.3%,22.8%~52.9%,13.1%~20.3% and 41.2%~53.7% in the 50 cm-depth soil, respectively.In addition, Agriophyllum squarrosum(L.) Moq.,Hedysarum mongdicum Turcz Var.,Salix cheilophila Schneid. and Caragana Korshinskii Kom.appear in the grassland with the growth of soil algal crust.The species diversity index, richness index and evenness index increased by 67.0%,82.4% and 57.9%,respectively.The plant production in the grassland changed from 58.5 g DW/m~2 to 241.6 g DW/m~2.These results indicate that the soil environment becomes better and the plant community structure and species diversity obviously get enhanced after inoculating soil algae in the degenerated grassland.Hence, soil algal crust is helpful for improving soil environment and accelerating ecological restoration of degenerated grassland.