不同建植年限人工草地植物群落和土壤有机碳氮特征

研究三江源人工草地的植物群落和土壤有机碳氮特征，有助于评价退化草地修复效果。本试验以天然草地和黑土滩作为对照，与建植5，12，19年的人工草地的植物群落土壤有机碳氮特征进行了比较。结果表明：人工草地的建植提高了地上生物量和植物群落盖度；不同草地植物群落组成存在差异。土壤有机碳和土壤全氮含量变化趋势呈现为：天然草地 > 人工草地 > 黑土滩。冗余分析表明，0~10 cm土层的含水量、容重、全氮含量和20~30 cm土层的pH是影响不通建植年限人工草地植物群落的主要因子。建植19年的人工草地植物群落相对稳定，但还未达到恢复为天然草地的状态，应加强人工草地的养分添加和土壤改良。

Characteristics of Plant Community and Soil Organic Carbon and Nitrogen in Artificial Grassland with Different Establishment Years

The study on plant community characteristics and soil organic carbon pool,nitrogen pool of artificial grassland is helpful for us to evaluate the restoration of degraded grassland in the Sanjiangyuan Region. In this experiment,native grassland and black soil land were used as control,and the characteristics of soil organic carbon and nitrogen of plant community were compared with those of artificial grassland for 5,12 and 19 years. The results showed that the establishment of artificial grassland increased the aboveground biomass and plant community coverage,and there were differences in plant community composition among different grasslands. The change trend of soil organic carbon and soil total nitrogen content is as follows:native grassland > artificial grassland > black soil land. Redundancy analysis(RDA)indicated that the soil moisture,bulk density,total nitrogen content of 0~10 cm soil layer and the soil pH value of 10~20 cm soil layer were the main factors influencing the plant community of artificial grassland. The plant community of 19-year old artificial grassland of establishment was gradually stable,but it had not completely recovered to the state of native grassland. Therefore,nutrient addition and soil improvement of artificial grassland should be strengthened.