管理方式对典型草原植物和土壤理化特征的影响

Effects of Management on Plant and Soil Physicochemical Characteristics of Typical Steppe

过度的放牧引起草地生态系统发生退化,而围封是恢复草地生态系统功能的有效管理措施。通过对不同管理方式(过度放牧、围封21年和围封34年处理)下内蒙古典型草地植物群落组成及土壤理化性质进行研究,结果表明:(1)不同草地管理方式通过改变优势植物种(羊草、大针茅和糙隐子草)的地上生物量,从而影响了植物群落地上净初级生产力;(2)围封处理显著增加了植物群落的地上生产力(P<0.05),且围封21年处理较高的物种多样性导致其植物群落生产力最高;(3)与长期过度放牧相比,围封21年和围封34年处理显著增加了土壤有机碳、总氮、总磷和土壤硝态氮的含量,而围封21年处理下土壤铵态氮含量显著高于围封34年处理。因此,研究结果建议合理的围封处理有利于草地生态系统的恢复。

Overgrazing leads to the degradation of the grassland ecosystem,whereas exclusion is an effective management measure to restore the grassland ecosystem function.The study aimed to study the plant community composition and soil physicochemical characteristics under different managements(overgrazing,grazing exclusion for 21 years,and grazing exclusion for 34 years)in Inner Mongolian typical steppe.The results showed that:(1)Different managements could affect the net primary productivity of plant communities by changing the aboveground biomass of dominant plant species(Leymus chinensis,Stipa grandis,and Cleistogenes squarrosa);(2)Grazing exclusion significantly increased the plant community aboveground primary productivity(P<0.05),in which treatment of grazing exclusion for 21 years had the highest values of these variables due to the high species diversity;(3)Compared with long-term overgrazing,both 21-year and 34-year grazing exclusion treatments significantly increased the contents of soil organic carbon,total nitrogen,total phosphorus,and nitrate nitrogen,while the soil ammonium nitrogen content was higher in the 21-year enclosure treatment compared with the 34-year enclosure treatment(P<0.05).Therefore,this study suggests that appropriate grazing exclusion treatment benefits the restoration of grassland ecosystems.