鼎湖山主要植被类型土壤微生物生物量研究

对鼎湖山国家级自然保护区3种主要植被类型：季风常绿阔叶林，针阔叶混交林和马尾松林土壤微生物生物量进行了研究。结果表明，土壤微生物生物量（mg.kg^-1）在季风常绿阔叶林、针阔叶混交林和马尾松林中分别为：822，588，530，季风常绿阔叶林显著高于针阔叶混交林和马尾松林（P〈0．01），而针阔叶混交林和马尾松林无显著差异（P〉0．05）；土壤中微生物量高的土壤中，有机碳含量也相应高，两者的比值可反应土壤碳的积累或损失，研究表明，鼎湖山3种主要植被类型土壤均处于碳积累过程；季风常绿阔叶林、针阔叶混交林和马尾松林土壤微生物碳周转量（t.hm^-2．a^-1）依次为：14．07，11．45，9，60，碳素的周转带动了其他营养元素的循环和能量的流动；土壤微生物代谢熵（mg.g^-1．h^-1）由低到高依次是季风常绿阔叶林（0．59）、针阔叶混交林（0．96）和马尾松林（1．33），表明土壤微生物对土壤碳的利用效率季风常绿阔叶林较高，马尾松林较低。

Soil microbial biomass of the main forests in Dinghushan Biosphere Reserve

Soil microbial biomass(Cmic) of three main vegetations in Dinghushan Biosphere Reserve(DBR),namely monsoon ever-green broadleaf forest(BF),mixed forest(MF) and pine forest(PF),was studied in April,2001 and March,2002.They were 822,588,530 mg.kg-1 in BF,MF and PF,respectively;with significant difference between BF and MF or PF(P<0.01),and no significant difference between MF and PF(P>0.05).Higher soil Cmic was accompanied by higher soil organic carbon(Corg).The ratios of Cmic to Corg,which indicate the accumulation or loss of soil carbon,showed that soil carbon was in the stage of accumulation in all three forests in the present study.More carbon turnover appeared in the soil with higher soil Cmic.The carbon turnover(t.hm-2.a-1) was 14.07 in BF,11.45 in MF and 9.60 in PF,respectively.The metabolic quotient(mg.g-1.h-1),which implies the efficiency of carbon utilization by soil microbes,was 0.59 in BF,0.96 in MF and 1.33 in PF,respectively.These metabolic quotients indicated that carbon utilization efficiencies were higher in BF and lower in PF.