向家坝水电站不同修复模式下根际土壤微生物化学计量特征

为探究水电站扰动区人工植被恢复后土壤质量及肥力的变化，以向家坝植被混凝土、厚层基材和框格梁3种典型边坡下优势物种荩草根际与非根际土壤为研究对象，对土壤的养分和微生物生态化学计量比进行研究。结果表明：（1）植被混凝土、厚层基材样地的养分平均含量均显著高于框格梁样地；植被混凝土、框格梁样地下土壤养分含量在根际存在一定的富集，以有机碳的富集作用最为明显，而厚层基材样地则表现为土壤全量养分在根际土壤中存在亏缺;（2）植被混凝土和框格梁修复模式样地的土壤微生物量为根际土壤较高，MBC/MBN、MBC/MBP表现为非根际土壤较高，3种样地下根际与非根际土壤微生物生态化学计量比差异性显著（P＜0.05）;（3）相关性分析表明，土壤微生物碳、微生物氮、有机碳和全氮之间具有显著的正相关性（P＜0.01），微生物量磷与土壤有机碳和全磷具有极显著的正相关性（P＜0.01）。综合评价十数年后向家坝水电站工程扰动区人工修复土壤技术，植被混凝土和厚层基材修复措施对该区土壤全量养分含量的累积作用较好，框格梁样地的植物生长发育受到磷素营养的限制较大。

Stoichiometric Characteristics of Rhizosphere Soil in Different Restoration Models of Xiangjiaba Hydropower Station

In order to explore the changes of soil quality and fertility after artificial vegetation restoration in disturbed area of hydropower station. The rhizosphere and non-rhizosphere soil of the dominant species of Arthraxon hispidus under three typical slopes of Vegetation Concrete Base Spraying technique(CBS), Thick Layer Base Material Spraying technique(TBS) and Framed beams soil covering(FBSC) were collected in Xiangjiaba Dam. And the soil nutrient and microbial ecological stoichiometric ratio were studied. The results showed that:(1) The average nutrient content of CBS and TBS was significantly higher than that of FBSC. The soil nutrient content of CBS and FBSC soil had a certain enrichment in the rhizosphere, and the enrichment of organic carbon was the most obvious, while the soil total nutrient of TBS was deficient in the rhizosphere soil.(2) The soil microbial biomass of the rhizosphere soil was significantly higher than the non-rhizosphere soil in the CBS and FBSC, MBC/MBN and MBC/MBP were higher in non-rhizosphere soil. The microbial ecological stoichiometric ratio was Significant differences in three ecological restoration models(P<0.05). The rhizosphere MBC/MBN of the TBS plot was significantly higher than that of the CBS and FBSC plots(P<0.05), while its MBC/MBN was lowest in the non-rhizosphere soil. The ratio of soil microbial carbon to phosphorus in rhizosphere and non-rhizosphere was FBSC>TBS>CBS.(3) The correlation analysis indicated that soil microbial biomass carbon, microbial biomass nitrogen, organic carbon and total nitrogen had significant positive correlation.(P<0.01). The microbial biomass phosphorus had a significant positive correlation with soil organic carbon and total phosphorus(P<0.01). Soil MBC/MBN only had a significant negative correlation with microbial nitrogen(P<0.01). Comprehensive evaluation of the artificial soil restoration technology in the disturbed area of Xiangjiaba Hydropower Station after more than ten years, CBS and TBS had a better effect on the accumulation of total nutrient content of soil in this area, plant growth and development of FBSC was limited by phosphorus nutrition.