小飞蓬入侵对伊犁河谷草原土壤有机碳的影响

Effects of invasion of Conyzacanadensis on soil organic carbon in Grassland of Yili Valley

为探讨小飞蓬入侵对伊犁河谷草原生态系统的影响,揭示小飞蓬的入侵机制,对不同入侵程度(轻度、中度、重度)小飞蓬及本地植物猪毛蒿根际土壤有机碳(SOC)、土壤容重和土壤含水量的变化规律进行研究。结果表明:随着小飞蓬入侵程度的加深,土壤SOC含量上升:小飞蓬重度、中度、轻度入侵和猪毛蒿群落土壤有机碳含量平均值分别为16.70、11.31、9.56 g·kg^-1和8.23 g·kg^-1,表明小飞蓬入侵增加了伊犁河谷草原土壤SOC的含量,随着入侵程度的加深,土壤SOC含量提高更加明显,同时增加了伊犁河谷草原土壤的碳汇功能。从垂直分布剖面上看,4个群落土壤SOC含量变化一致:随着土壤深度的增加而SOC含量减少,且最大土壤SOC含量均出现在0~20 cm土层,小飞蓬重度、中度、轻度入侵和猪毛蒿群落最大土壤SOC含量分别为:20.3、15.0、13.2 g·kg^-1和11.5 g·kg^-1。小飞蓬重度、中度、轻度入侵和猪毛蒿群落土壤容重平均值分别为5.02、4.94、4.85 g·kg^-1和5.09 g·kg^-1,土壤含水量平均值分别为1.22%、1.20%、1.19%和1.24%,表明小飞蓬的入侵改变了伊犁河谷土壤物理性质,随着小飞蓬入侵程度的加深不断降低土壤容重与含水量,土壤含水量与土壤容重存在极显著的正相关性(P<0.01),结合土壤SOC进行分析,发现土壤容重与含水量对土壤SOC的影响一致,均呈现极其显著的负相关性(P<0.01)。

In order to reveal the invasion mechanism of the Conyzacanadensis,and explore its influence on grassland ecosystem in Yili Valley,the evolution of soil organic carbon(SOC)in the rhizosphere of Conyzacanadensis with different invasion degree(mild,moderate,severe)and the local plant of Artemisia scoparia Waldst.et Kit.were analyzed.The results showed that the soil SOC content increased with the deepening of the invasion of Conyzacanadensis:the severe,moderate,and the mild invasion of Conyzacanadensis,and the average soil values of Artemisia scoparia Waldst.et Kit.were 16.70,11.31,9.56,8.23 g·kg^-1.It is indicated that the invasion of Conyzacanadensis increased soil SOC content.With the deepening of the invasion,the ability to increase soil SOC was more obvious.At the same time,the carbon sink function of the grassland soil in the Yili River Valley increased.From the vertical distribution profile,the soil SOC content of the four communities changed uniformly:it decreased with the increase in soil depth,and the maximum soil SOC values all appeared in the 0~20 cm soil layer.The severe invasion of Conyzacanadensis,the moderate invasion of Conyzacanadensis,the mild invasion of Conyzacanadensis,and the maximumsoil SOC values of Artemisia scoparia Waldst.et Kit.were 20.3,15.0,13.2 g·kg^-1 and 11.5 g·kg^-1.The severe invasion of Conyzacanadensis,the moderate invasion of Conyzacanadensis,the mild invasion of Conyzacanadensis,and soil bulk density values of Artemisia scoparia Waldst.et Kit.were 5.02,4.94,4.85 g·kg-3 and 5.09 g·kg-3.The average values of soil water content were 1.22%,1.20%,1.19%,and 1.24%.It showed that the invasion of Conyzacanadensis changed the physical properties of the soil in the Yili River Valley.As the invasion of Conyzacanadensis was deepened,the soil bulk density and water content were continuously reduced.There was a very significant positive correlation between water content,soil water content,and soil bulk density(P<0.01).Based on the analysis of soil SOC,it was found that the effects of soil bulk density and water content on soil SOC were consistent,and all showed extremely significant negative correlations(P<0.01).