Abstract: This study took the Sophora alopecuroides,the dominant population in the tuohulasu grassland of Yili River Valley,as the research object. Distribution characteristics of soil microbial biomass carbon (MBC),water-soluble organic carbon (WAOC),readily oxidizable organic carbon (POC) under different altitude gradients and the influencing factors were examined to investigate the impact of the spreading of Sophora alopecuroides on the soil ecological environment and to understand the mechanism of poisonous grass spreading in Yili Valley,in hopes to providing theoretical basis for poisonous grass control. The results showed that soil microbial biomass carbon increased with the increase of altitude and decreased with the deepening of soil layer. However,soil water-soluble organic carbon and easily oxidized organic carbon increased with the increase of altitude and deepening of soil layer. According to the correlation analysis,the correlation between the three components of soil active organic carbon and total organic carbon,total nitrogen and soil moisture reached the significant level (P<0.01),and the three components were also significantly correlated with each other. The results showed that altitude,total nitrogen content and total organic carbon had significantly impacted the content of AOC in Sophora alopecuroides population.

Key words: Yili Valley, Different Altitudes, Sophora alopecuroides, Soil Active Carbon Components, Influencing Factors

摘要： 本研究以伊犁河谷托乎拉苏大草原占据优势的苦豆子（Sophora alopecuroides）种群为研究对象，通过对不同海拔梯度下土壤微生物量碳、水溶性有机碳和易氧化有机碳含量的分布特征及其影响因素研究，解析苦豆子蔓延对土壤生态环境的影响，为了解伊犁河谷草原毒害草蔓延机制及提供草原毒害草管控措施提供理论依据。结果表明：土壤微生物量碳随着海拔的上升而增加，随土层的加深而降低；而土壤水溶性有机碳和易氧化有机碳均随海拔、土层的增加而增加。根据相关性分析可知，土壤活性有机碳的3种组分与总有机碳、全氮以及土壤湿度3个指标之间相关性达到极显著水平（P<0.01）；且3种组分之间也相互存在显著相关。研究表明海拔、全氮含量以及总有机碳3个指标显著影响苦豆子种群活性有机碳含量的变化。

关键词: 伊犁河谷, 不同海拔, 苦豆子, 土壤活性碳组分, 影响因素