摘要
研究了浙江天童常绿阔叶林植被5个主要退化阶段土壤微生物主要类群数量分布特征。采用涂布平板法和MPN法(最大可能数法)进行三大微生物类群(细菌、放线菌和真菌)和氨化细菌等重要功能微生物的分析。测定时间为2003年7月和2004年2月。以考察常绿阔叶林退化过程中土壤微生物主要类群变化特性,为退化生态系统的恢复和重建提供基础研究。结果表明,从栲树林至灌木的5个主要退化阶段,0～20cm土壤层中细菌较真菌和放线菌的数量分布占绝对优势。2003年7月和2004年2月细菌占三大微生物总数平均比例分别为73.4%和85.6%。土壤微生物总数的变化同土壤全氮、土壤有机质含量及土壤肥力综合指标的变化呈显著相关性。2003年7月和2004年2月土壤层氨化细菌、固氮菌、纤维素分解菌、硝化细菌四类主要微生物生理类群中,氨化细菌占绝对优势,占四类微生物生理类群的平均比例分别为98.3%和94.3%,在森林凋落物分解过程起重要作用。从栲树林至灌木林的5个退化阶段,三大微生物数量、微生物总量、四类主要微生物生理类群数量总体呈下降趋势,尤其以冬季变化趋势明显。2004年2月从1#栲树林至5#灌木林,细菌数量下降80.4%,微生物总数下降82.2%,固氮菌减少99.1%,氨化细菌减少96.8%,纤维素分解菌减少95.8%,硝化细菌减少99.8%。随着植被的退化演替,土壤肥力降低,土壤环境条件不利于微生物的生长。土壤主要微生物生理类群数量的减少削弱了土壤中C、N等营养元素的循环速率和能量流动。
The present article intends to introduce the authors＇ study on the eco-microscopic distribution characteristics of the main soil groups in its five degradation stages of evergreen broad-leaved forests in Tiantong Area, Zbejiang, by using the spread-plate and MPN methods during the period from July, 2003, to February, 2004. The purpose of the study is to analyze and find the actual distribution of the three major micro-organisms （bacteria, fungi and actinomyces） and their corresponding physiological microscopic groups （ammonitiers, nitrogen fixing bacteria, cellulose decomposing bacteria, and nitrobacteria） so as to provide a theoretical basis for the restoration and reconstruction of degraded ecosystem. The results of the study indicate that, in the 0 - 20 cm soil layer of the five retrogress states, from 1^# Castanopsisfagasii to 5^# the shrub forest, bacteria predominated among the above three groups, bacteria, fungi and actinomyces. Bacteria had a large amount of about 73.4 % and 85.6 % within the total soil microorganisms, separated in July 2003 and February 2004, much more than fungi and actinomyces. Our study has also shown that amounts of total soil microorganisms were in high correlation with content of the total nitrogen, soil organic matter and soil fertility. Among the four major physiological groups including ammonifiers, nitrogen fixing bacteria, cellulose decomposing bac- teria, and nitrobacteria, ammonifiers amounted to 98.3 % and 94.3 % respectively. Among the degradation stages from Castanopsis fagasii to Shrubs, a tendency has been observed with the reduction of bacteria and the total amounts of soil microbes, the same as four major physiological groups, especially in winter. From Castanopsis fagasii to Shrub forest, in February 2004, bacteria amounts were dropped by 80.4%, as such, 81.8% for total amounts of microorganisms, 99.1% for nitrogen fixing bacteria, 96.8 % for ammonifiers, 95.8 % for cellulose decomposing bacteria, and 99.8% for nitrobacteria. With the degeneration of plant communities, soil fertility has dropped, and the soil conditions becomes poorer and poorer for microorganisms to grow. And in turn the decrease in major soil physiological groups weakened the circulation rate and energy flow of nutrition elements such as nitrogen and carbon.
出处
《安全与环境学报》
CAS
CSCD
2005年第4期61-64,共4页
Journal of Safety and Environment
基金
上海市生态学重点学科和国家高技术研究发展863计划专项资助(2003AA601020)
关键词
土壤生态
土壤微生物
退化演替
常绿阔叶林
浙江天童
soil ecology
soil microorganism
degradation succession
evergreen broad-leaved forest
Tiantong
