氮添加对内蒙古典型草原土壤动物的影响  

Effect of nitrogen addition on soil fauna in a temperate steppe of Inner Mongolia

作　　者：程建伟 郝百惠 刘新民[2] 马文红 李永宏[1] Cheng Jian-wei;Hao Bai-hui;Liu Xin-min;Ma Wen-hong;Frank Yonghong Li(Key Laboratory of Grassland Ecology, School of Ecology and Environment, Inner Mongolia University, Hohhot 010021, Inner monggolia, China;College of Life Science and Technology, Inner Mongolia Normal University, Huhhot 010022, Inner Mongolia, China;SINO-US Center for Conservation, Energy and Sustainability Science, Inner Mongolia University, Hohhot 010021, Inner Mongolia, China)

机构地区：[1]内蒙古大学生态与环境学院草地生态学国家重点实验室培育基地,内蒙古呼和浩特010021 [2]内蒙古师范大学生命科学与技术学院,内蒙古呼和浩特010022 [3]内蒙古大学中美生态能源及可持续性科学研究中心,内蒙古呼和浩特010021

出　　处：《草业科学》2018年第5期1254-1265,共12页Pratacultural Science

基　　金：国家自然科学基金(31160119;31370454)

摘　　要：氮是陆地生态系统的主要限制元素,氮输入的变化影响陆地生态系统生物群落结构和功能过程。目前有关氮添加的研究主要集中在植物群落,而对土壤动物影响的研究较少。本研究在内蒙古典型草原区设计了氮素添加试验,研究了在4个氮添加[对照(N0)、低氮(N2.5)、中氮(N5)、高氮(N10)]水平下草原凋落物层土壤动物主要功能类群的群落结构变化,并分析了其与环境因子之间的关系。结果表明,低氮和中氮添加显著促进土壤动物的多度,而高氮添加显著降低土壤动物的多度和多样性(P<0.05)。土壤动物的不同功能群对氮输入增加的响应不同,捕食性和腐食性功能群多度在高氮处理下显著减少(P<0.05),而植食性和杂食性动物功能群多度则不随氮添加水平变化(P>0.05)。冗余分析(RDA)显示,中气门亚目若螨(Mesostigmata nymphs)和厉螨科(Laelapidae)等类群的多度与氮添加水平呈显著负相关关系(P<0.05);而等节跳科(Isotomidae)和长角跳科(Entomobryidae)等类群的多度变化主要受氮添加引起植物物种丰富度、土壤SOC和凋落物pH改变的间接影响。研究结果表明,适量氮添加可增加凋落物层土壤动物群落的多度,但较高的氮供应[10g·(m2·a)-1]则降低土壤动物群落的多样性。Nitrogen（N）addition effects on plant and soil biota,and functional processes of terrestrial ecosystems were studied.The response of soil fauna to nitrogen addition has not yet been well studied in comparison to the studies on the response of plant communities.Here,we studied the effects of N addition on soil biota in a semi-arid steppe community in central Inner Mongolia using a field experiment.The experiment consisted of four N addition levels,applied by adding N fertilizers at four rates,including：0（control）,25（low）,50（medium）,and 100（high）kg·ha-1.After 5 years of treatments,we examined the changes in soil fauna communities and their functional groups in response to different N treatments,and analyzed their relationships with environmental factors.The results showed that N addition at the low and medium levels enhanced the abundance of soil fauna by 75.8% and 76.7%,respectively,in comparison to that of the control,where as N addition at the high rate significantly decreased the diversity of soil faunas.The responses of soil fauna to N addition varied among functional groups.The abundance of predatory and saprophagous fauna decreased by 69.1%and 54.4%,respectively,under the high N treatment;whereas the phytoplasmic and omnivorous functional groups showed no significant changes under different N treatments.The results of RDA analysis also detected a significant negative correlation between the abundance of Mesostigmata nymphs and Laelapidae and N addition rates,and the abundance of Isotomidae and Entomobryidae were indirectly affected by N addition through the effects on plant species richness,soil organic carbon,and litter pH.Our results indicated that low N addition rates may enhance the abundance of soil fauna in the litter layer of steppe ecosystems,whereas a high N addition rate[〉10 g ·（m2·a）-1]may decrease the diversity of soil fauna.

关 键 词：氮输入增加 凋落物层 群落结构 功能群 多度 多样性 

分 类 号：S812.2[农业科学—草业科学]