氮添加对苏北杨树人工林土壤动物群落结构的影响

发布时间：2018-05-10 10:35

本文选题：氮沉降 + 林龄　；参考：《南京林业大学》2015年硕士论文

【摘要】：人类活动引起的氮沉降对全球生物多样性和生态系统服务功能是一个巨大的威胁,土壤动物对环境变化反应敏感,氮沉降可能显著影响森林土壤动物群落结构。从2012年5月起,在东台林场三个不同林龄杨树人工林(黑杨派无性系I-35,Populus deltoides cv.‘I-35’)进行野外模拟氮沉降试验,共设置5个处理,即对照、5、10、15、30 g N·m-2·a-1氮添加。在氮添加控制试验进行3个生长季后,探讨氮沉降对不同林龄(6、10、17年生)杨树人工林土壤动物群落的影响。结果表明:(1)随着林龄增长,林分土壤动物群落个体密度增加,土壤动物的物种丰富度下降;主要表现为优势类群甲螨亚目、前气门亚目的个体密度随林龄的增长而增加。凋落物层的土壤动物密度小于土层,并且在6年生林最大,而土壤层中却相反。随土层的加深,土壤动物数量和类群数均呈下降趋势。(2)土壤动物群落在各月份出现的类群数大小依次为:6月9月3月12月。随取样时间,各林龄林分土壤动物总密度有不同的变化趋势,密度最小的月份都为12月,6月和9月密度较大。(3)土壤动物密度随施氮浓度增加呈现先上升后下降的趋势;15和30 g N·m-2·a-1浓度氮添加增加了土壤动物的优势度,使得多样性和均匀性降低;氮添加对各层土壤动物密度的增加有促进作用,特别是10和15 g N·m-2·a-1中等浓度的氮添加,但氮添加并没有改变土壤动物群落的表聚性特征。(4)15和30 g N·m-2·a-1浓度氮添加引起土壤pH值和C/N值呈下降趋势,NO3--N和TN含量增加,从而导致土壤动物群落的密度、类群数和多样性的降低。土壤动物群落多样性的时间变化规律与气温和降雨量的季节变化规律一致。
[Abstract]:Nitrogen deposition caused by human activities is a great threat to global biodiversity and ecosystem service function. Soil animals are sensitive to environmental changes and nitrogen deposition may significantly affect forest soil fauna community structure. Field simulated nitrogen deposition experiments were carried out in three poplar plantations of different ages (I-35Populus deltoides cv. I-35) in Dongtai Forest Farm from May 2012. Five treatments were set up, namely, the control was 101530g N m-2 a-1 nitrogen addition. The effects of nitrogen deposition on soil fauna community of poplar plantations were studied after three growth seasons with nitrogen addition control test. The results showed that with the increase of forest age, the individual density of soil fauna community increased, and the species richness of soil fauna decreased. The density of soil fauna in litter layer was lower than that in soil layer, and was the highest in 6 years old forest, but opposite in soil layer. With the deepening of soil layer, the number of soil fauna and group showed a downward trend. 2) the number of soil fauna community in each month appeared in order: June, September, March, December. With the sampling time, the total density of soil animals varied in different stand ages. In June and September, the density of soil animals increased first and then decreased with the increase of nitrogen concentration. The density of soil animals increased the dominance of soil animals by adding nitrogen concentration of 15 and 30 g N m-2 a-1. Nitrogen supplementation promoted the increase of soil animal density, especially the addition of 10 and 15 g N m-2 a-1. However, nitrogen supplementation did not change the characteristics of soil fauna community's apparent aggregation. The addition of N at concentrations of 415 and 30g N m-2 a-1 resulted in the decrease of soil pH value and C / N value, and the increase of no _ 3 N and TN contents, which resulted in the density of soil fauna community. Reduction of group number and diversity. The temporal variation of soil animal community diversity is consistent with the seasonal variation of temperature and rainfall.
【学位授予单位】：南京林业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S714.3

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