作　　者： ; ; ; ;

机构地区： 中国科学院研究生院

出　　处： 《生态环境》 2005年第6期901-907,共7页

摘　　要： 研究了南亚热带3种森林生态系统凋落物在N沉降下的分解动态及其与土壤动物群落的关系。选取季风常绿阔叶林、针阔混交林和马尾松林建立野外模拟N沉降样地,实施四个处理组,对照(Control)、低氮(50kg·hm-2·a-1,LowN)、中氮(100kg·hm-2·a-1,MediujmN)和高氮处理(150kg·hm-2·a-1,HighN),利用凋落物网袋法,在18个月的时间内调查分析了凋落物分解过程及其中的土壤动物密度特征。研究结果表明,植被演替阶段对凋落物的分解速度存在影响,季风林凋落物降解速度显著性快于混交林和针叶林(P<0.05);18个月后,季风林各处理地凋落物残留率为0.05、0.14、0.13和0.17,混交林为0.64、0.56和0.62,针叶林为0.66、0.63和0.62。N沉降增加对凋落物分解存在一定影响。且这种影响与植被类型之间存在明显的交互作用。N沉降处理对季风林凋落物分解表现出了一定的抑制作用,而且这种差异随时间推移愈益明显,但在混交林和针叶林内,试验后期凋落物分解受到了N沉降处理的促进作用。在试验后期,尤其是12个月后,凋落物网袋土壤动物密度在不同林地和不同水平N处理下体现了差异化发展趋势。在季风林内,N处理地土壤动物密度受到了明显的抑制;在混交林和针叶林内,低N样地动物密度显示了相比对照样地的明显优势,但在较高强度的中N处理地无论在凋落物的降解速率还是在动物密度上都与对照样地没有明显差别。文章认为,N沉降处理所产生的影响可能受环境N饱和程度的调控。文章还提出,在凋落物分解进程中,土壤动物群落具有“后期进入”特征,这对于进一步准确分析森林凋落物分解进程及土壤动物的贡献有重要意义。 The dynamic of litter decomposition and its relationship with soil fauna in three forests in subtropical China was studied for 18 months by litter bag in this paper. Field plots were built in monsoon evergreen leaf-broad, pine and leaf-broad mixed and pine forests （MEBF, PF and MF） in subtropical China to simulated N deposition addition, and treatments included control （No addition）, low N deposition （50kg·hm^-2·a^-1）, middle N deposition （100kg·hm^-2·a^-1） and high N deposition （150 kg·hm^-2·a^-1） by spreading water or NHnNO3. It suggested that litter decomposition were affected by forest succession stage. Litter in MEBF decomposed significantly faster than in MF and PF （P〈0.05 ） ： after decomposing for 18 months, the mean fraction of initial mass of decomposing litter remaining in every treatment in MEBF was 0.05, 0.14, 0.13 and 0.17, was 0.64, 0.56 and 0.62 in MF and was 0.66, 0.63 and 0.62 in PF. N addition also influenced litter decomposition in a certain, and interacted with forest type. There was a certain negative effect of N treatment on litter decomposition in MEBF, and the trend enlarged with time. But litter decomposition increased under N addition in MEBF and PF in the later experimental stage. Soil fauna density in litter bag varied with forests and N treatment in the later experimental stage, especially after 12 months. There was obvious negative effect of N addition on soil fauna density in MEBF. Low N addition conducted positive effects on soil fauna density compared with control plot in MF and PF, but it did not appear in medium plot compared with control plot. It was discussed that the effects from N treatment might be explained by the N status of ecosystem. The “later entrance” of soil fauna in the process of litter decomposition was also proposed and it was considered to be valuable in the further studies on litter decomposition and soil fauna contribution.

关 键 词： 沉降 凋落物 土壤动物

领　　域： [生物学] [农业科学] [农业科学]