望天树天然林土壤微生物生物量碳氮垂直分布及相关性分析

Vertical Changes of the Soil Microbial Biomass and the Correlation Analysis in Parashorea chinensis Natural Forest

选取广西田阳县望天树Parashorea chinensis天然林、油茶Camellia oleifera人工林及桉树Eucalyptus robusta人工林为研究对象,通过氯仿熏蒸浸提法对微生物生物量C、N以及诸因素的垂直变化进行了研究。研究结果表明:3种林分土壤微生物生物量C、N均随着土层深度显著下降(P<0.05),其中不同林地0～10 cm土壤微生物生物量C差异最大,20～40 cm土壤微生物生物量N差异最大;0～10 cm望天树天然林微生物生物量C分别比油茶人工林、桉树人工林高1.41倍、1.63倍,20～40 cm微生物生物量N分别比油茶人工林、桉树人工林高1.54倍、2.87倍。相关性分析表明,3种林分微生物生物量C、N均与土壤全氮、速效钾呈极显著(P<0.01)的正相关。综上所述,目前,望天树天然林各土层土壤微生物生物量C、N均保持在良好水平,土壤深度、土壤养分、林分组成等能对土壤微生物生物量碳氮产生显著影响。

In this paper,the soil microbial biomass and relative factors were studied of a natural forest of Parashorea chinensis(PF),planted forest of Camellia oleifera(CF)and planted forest of Eucalyptus robusta(EF)in Guangxi Tianyang by chloroform fumigation method.The results showed as follows.The microbial biomass C and N of 3 species of soil were significantly decreased with soil depth(P<0.05).The difference of soil microbial biomass C of 0-10 cm was the largest in 3 species and soil microbial biomass of 20-40 cm was the most significant difference.The microbial biomass C of 0-10 cm PF was1.41 times and 1.63 times that of CF,EF.The microbial biomass N of 20-40 cm PF was1.41 times and 1.63 times that of CF,EF.The correlation analysis showed that the microbial biomass C and N were positively correlated with total N and available K(P<0.01).To sum up,at present,the soil microbial biomass C and N of each soil layer in PF were maintained at good level.Soil depth,soil nurients and forest components had a significant effect on soli microbial biomass C and N.