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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 dynamics of litter decomposition in three subtropical forest ecosystems under N deposition and its relationship with soil fauna community were studied. Four monsoon evergreen broad-leaved forests, conifer and broad-leaved mixed forests and Pinus massoniana forests were selected to establish field simulated N-subsidence plots. Four treatment groups were selected as control, low nitrogen (50 kg · hm-2 · a-1, LowN) Medium-nitrogen (100 kg · hm-2 · a-1, MediujmN) and high-nitrogen treatment (150 kg · hm-2 · a-1, HighN) were analyzed by litter bag method within 18 months Litter decomposition process and the characteristics of soil animal density. The results showed that the litter decomposition rate was affected by vegetation succession stage, and the litter degradation rate in monsoon forest was significantly faster than that in mixed forest and coniferous forest (P <0.05). After 18 months, the monsoon forest litters The residual rate was 0.05,0.14,0.13 and 0.17, the mixed forest was 0.64, 0.56 and 0.62, the coniferous forest was 0.66, 0.63 and 0.62. N deposition has some effect on the litter decomposition. There is a clear interaction between this effect and the type of vegetation. N deposition decreased the litter decomposition of monsoon forest, and the difference became more and more obvious with the passage of time. However, in the mixed forest and coniferous forest, litter decomposition was promoted by N deposition in the later stage of the experiment. At the later stage of the experiment, especially after 12 months, the density of litter net soil bag animals showed the trend of differentiated development under different woodlands and different levels of N treatment. In the monsoon forest, the density of soil animals in N-treated area was significantly inhibited. In mixed forest and coniferous forest, the density of animals in low-N-plot showed obvious superiority compared with that in the control plot. However, There was no significant difference between the litter degradation rate and the animal density in comparison with the control plots. The article argues that the impact of N deposition may be influenced by the degree of N saturation in the environment. The article also proposed that in the process of litter decomposition, soil fauna has “late entry” characteristics, which is of great significance for further accurate analysis of litter decomposition process and soil fauna contribution.