摘要：
C,N and P are the main obj ects of ecological stoichiometry,which can be used to character-ize plant nutrient utilization and response to environmental changes.In the study,through comparing the C,N,P changes of plants,roots and soil in graze,enclosure for 2 years and enclosure for 9 years,the effects of enclosure on nutrients and stoichiometric ratio were reveal in the Seriphidium transiliense desert grassland ecosystem.The results showed that the soil organic carbon did not change greatly,the total ni-trogen increased steadily,and the total phosphorus decreased slightly after fenced.In grassland of enclo-sure for 2 years,the N/P values of plants and roots in 0~5 cm soil layer were higher than that of graze,in-dicating that the utilization rate of N was higher in the early stage of grassland restoration.After enclosure for 9 years,the N/P values of plants and roots decreased,showing that the utilization of P was improver after long-term restoration.The enclosure measure had little effect on the C/N of plants,but the C/N of the roots were increased in the long-term enclosure,indicating that the long-term enclosure increased car-bon sequestration of root significantly.The correlation analysis showed that there were no significant cor-relations among soil P,community P and root P,but root P was related to root C,plant N and soil C, showing that the absorption and utilization of P element in plants were indirectly affected by the other ele-ments in the environment of soil phosphorus deficiency in arid region.%对比干旱区伊犁绢蒿荒漠草地放牧、封育2年、封育9年的植被、根系及土壤 C、N、P 元素的变化,以揭示封育对生态系统养分及其化学计量比的影响.结果表明,封育后土壤有机碳含量变化不大,全氮含量稳步提高,全磷含量稍有降低.封育2年的植被和0~5 cm土层根系的 N/P高于放牧,表明恢复初期植物对 N的利用率较高;封育9年的植被和根系 N/P降低,表明植被恢复后植物对 P 素的利用率提高.封育对植被的 C/N 影响不大,但长期封育使根系的C/N升高,表明长期封育使根系固碳显著.相关分析表明,土壤 P、植被 P、根系 P 之间没有显著相关,但是根系P与根系C、植被 N和土壤C显著相关,表明在干旱区土壤缺磷的环境下,植物对P素的吸收与利用是通过其他元素来间接影响的.
