摘要
外来入侵植物对土壤生态系统的影响已成为入侵生态学研究的热点问题。以我国典型入侵植物水花生(Alternanthera philoxeroides,Ap)和苏门白酒草(Conyza sumatrensis,Cs)为对象,选取撂荒的稻田为试验样地,以土著优势物种马唐(Digitaria sanguinalis,Ds)为参照,通过对入侵植物和土著植物的根际土壤进行采样分析,研究了入侵植物对入侵地土壤特性及土壤碳氮过程的影响。结果表明,与土著物种Ds相比,Ap和Cs入侵分别使土壤有机质含量增加106和27,全氮量增加63和97,铵态氮含量增加97和94,硝态氮含量增加71和243,微生物量碳增加123和225,微生物量氮增加225和399,氮净矿化速率增加2.1倍和3.8倍,反硝化速率增加1.0倍和0.8倍,酶的活性和硝化速率亦显著增加;矿化过程中Cs和Ap的CO2平均排放速率分别增加2.3倍和2.6倍,土壤N2O的平均排放速率分别增加1.9倍和2.2倍。由此可见,入侵植物显著地改变了入侵地土壤的理化特性,加速了土壤碳氮转化过程,呈现正反馈效应。
Alien species invasion has become one of the three global environmental problems due to its tremendous effects on community structure and ecosystem function.Recently,many studies have devoted to documenting the impact of exotic plant invasions on ecosystem processes.To examine the effects of alien plants invasion on soil properties and soil processes,we collected rhizosphere soil samples under invasive plants,Conyza sumatrensis（Cs） and Alternanthera philoxeroides（Ap）,and the neighboring indigenous species,Digitaria sanguinalis（Ds） in a deserted paddy field.The results showed that alien invasive plants relative to neighboring indigenous plants increased soil organic carbon and nitrogen contents.Compared with the Ds,the soil organic carbon content,total nitrogen,nitrate and ammonium contents were increased by 106%,63%,97% and 71% for the invasive Cs,and 27%,97%,94% and 243% for the invasive Ap,respectively.Soil microbial carbon and nitrogen biomass were increased by 123% and 225% for the Cs,and 225% and 339% for the Ap,respectively.Under similar laboratory incubation conditions,soil mineralization and denitrification rates were increased by 210% and 100%,or 380% and 80% due to the Cs or Ap invasion relative to the Ds,respectively.In contrast with the Ds,soil CO2 emission and N2O emission rates were as high as 1.9~2.3 and 2.2~2.6 times for the Cs and Ap,respectively.Similarly,the Cs and Ap invasion significantly increased rhizosphere soil enzyme activity and nitrification rates.Therefore,the results of this study revealed a significant shift in soil properties due to alien plants invasion.Soil carbon and nitrogen process was substantially facilitated,which may create a positive feedback as a consequence of alien plants invasion.
出处
《农业环境科学学报》
CAS
CSCD
北大核心
2011年第4期797-805,共9页
Journal of Agro-Environment Science
基金
教育部新世纪优秀人才支持计划(NCET-08-0798)
全国博士后特等资助项目(200801379)
国家重点实验室开放课题(LAPC-KF-2009-03)
关键词
水花生
苏门白酒草
入侵植物
土壤过程
碳氮过程
Alternanthera philoxeroides
Conyza sumatrensis
invasive species
soil process
soil carbon and nitrogen process
