氮添加对苏北杨树人工林土壤动物群落垂直结构的影响

Effects of nitrogen addition on soil animal community vertical structure in Northern Jiangsu poplar plantation

为研究氮沉降对杨树人工林土壤动物群落结构特征的影响,在东台林场模拟氮沉降固定样地(2012年4月开始施氮)中进行了土壤动物群落结构特征调查。在经营模式、立地条件相同的7,11,18年生的3林龄杨树人工林样地,设置5个不同质量梯度的氮沉降处理,即0(N0),5(N1),10(N2),15(N3),30(N4)g N/(m2·a)。结果表明:(1)施氮处理会增加杨树人工林土壤动物个体数,而N4处理只对11年生林分和18年生林分中土壤动物个体数有一定的限制作用。(2)不同施氮浓度下,7,11年生人工林中土壤动物个体数和类群数均呈现表聚性,18年生林分土壤动物也只是在N4处理下表现出向土壤深层趋避的特点。(3)总体上7年生林分土壤动物多样性高于11年生林分和18年生林分。

A nitrogen addition experimental site was set up in Apr., 2012 with the aged 7,11 and 18 forests and different concentrations of nitrogen addition as 0（N0） ,5（N1） ,10（N2） ,15（N3） ,30（N4） g N/（m2 · a） to study the responses of soil fauna community structure to N addition in poplar plantation of Northern Jiangsu, China. The results showed that （1） N addition promoted the individual numbers of soil fauna; meanwhile, the limitations of individual numbers of soil fauna were ob- served under N4 treatment in the aged 11 and 18 forests. （2） The surface convergences were found in the aged 7 and 11 forests and all nitrogen deposition concentrations. Even in the aged 18 forest, only under 514 treated soil, fauna preferred to move to the deeper layer. （3） In generally, the species diversity was higher in the aged 7 forest than in the aged 11 and 18 forests.