沙地樟子松人工林土壤理化性质与微生物生物量的动态变化

Dynamics of soil physicochemical properties and microbial biomass in a Pinus sylvestris var.mongolica plantation

为揭示不同林龄沙地樟子松人工林土壤理化性质和微生物生物量的动态和相互关系,以毛乌素沙地、科尔沁沙地和呼伦贝尔沙地不同林龄樟子松人工林为对象,分析土壤理化性质、土壤微生物生物量碳和微生物生物量氮变化规律。结果表明:樟子松人工林土壤理化性质随林龄增加在不同沙地中表现不同,毛乌素沙地土壤容重和养分含量明显降低,科尔沁沙地土壤孔隙度和养分含量明显升高,呼伦贝尔沙地土壤养分则呈现先增加后降低趋势。与土壤理化性质变化趋势类似,毛乌素沙地樟子松人工林土壤微生物生物量氮随着林龄的增加而降低,科尔沁沙地土壤微生物生物量氮随着林龄的增加而升高,呼伦贝尔沙地土壤微生物生物量氮随着林龄的增加呈先增加而后降低趋势。影响毛乌素沙地、科尔沁沙地和呼伦贝尔沙地土壤微生物生物量碳、氮的主要因子分别是硝态氮、铵态氮和有机质含量。毛乌素与科尔沁沙地樟子松人工林主要限制因子为土壤氮,而呼伦贝尔沙地樟子松受土壤有机碳限制较强。

To reveal the dynamics of soil physicochemical properties and microbial biomass as well as their relationships in Mongolian pine(Pinus sylvestris var.mongolica)plantations with different stand ages,we examined soil physicochemical properties and soil microbial biomass C(MBC)and N(MBN)in Mongolian pine plantations of various ages in Mu Us,Horqin,and Hulunbuir sandy lands.The results showed that changes of soil physicochemical properties with increasing stand age differed among different sandy lands.In the Mu Us Sandy Land,soil bulk density and soil nutrients significantly decreased.In the Horqin Sandy Land,soil porosity and nutrients significantly increased.In the Hulunbuir Sandy Land,soil nutrients increased first and then decreased.With increasing stand age,soil MBN decreased in the Mu Us Sandy Land,increased in the Horqin Sandy Land,and increased first and then decreased in the Hulunbuir Sandy Land.The major factors affecting soil MBN were the concentrations of nitrate,ammonium,and organic matter in the Mu Us,Horqin,and Hulunbuir Sandy Land,respectively.Soil nitrogen was the main limiting factor of Mongolian pine plantation in the Mu Us and Horqin Sandy Land,while soil organic carbon was the main limiting factor in the Hulunbuir Sandy Land.