闽西天然常绿阔叶林土壤碳氮化学计量特征的小尺度变异

Fine-scale variation of soil carbon and nitrogen stoichiometry in a natural evergreen broad-leaved forest in western Fujian

本研究分析了福建省西部一个亚热带天然常绿阔叶林的土壤全碳、全氮含量以及碳氮比(C:N)的小尺度空间分布格局.土壤样品取自3个坡位(上坡、中坡和下坡),按离树干不同距离(50,100,150,200,250,300,350 cm),分5层(0~3,3~6,6~9,9~12,12~15 cm)取土.结果表明,土壤全碳、全氮含量随土层加深而减小,土壤C:N则随土层加深而增加.上坡的土壤全碳、全氮含量低于下坡,土壤C:N在3个坡位之间无显著差异.总体来说,土壤全碳、全氮含量随着离树干水平距离增加而减小.在所有3个尺度上,土壤全碳和全氮含量正相关;土壤C:N与全碳、全氮、可溶性有机碳(dissolved organic carbon,DOC)含量均无相关性.这些结果表明,闽西亚热带天然林土壤碳氮含量和C:N在小尺度上存在较大变异.

In this paper,the fine-scale spatial patterns of soil total carbon(TC),total nitrogen(TN)and C:N were analyzed in a subtropic natural evergreen broad-leaved forest in western Fujian.Soil samples were collected from five depths(0-3,3-6,6-9,9-12,12-15 cm)and at seven horizontal distances(50,100,150,200,250,300,350 cm)from the tree trunks and along three slope positions(upper,middle and lower).The results showed that the soil TC and TN decreased along soil depth,but increased in soil C:N.The soil TC,TN were lower in the upper slope than those in the lower slope,and there was no significant difference in C:N among the three slope positions.In general,the soil TC,TN decreased with the increasing distance from the tree trunks.At all the three scales,soil TC was significantly related to TN,and C:N was not correlated with any measured soil variable[TC,TN and dissolved organic carbon(DOC)]significantly.These results showed a significant fine-scale variation in soil carbon content,nitrogen content and C:N in the subtropic natural forest in western Fujian.