山西太岳山典型植被类型土壤微生物量特征

Soil microbial biomass properties under typical vegetation types in the Taiyue Mountain of China

以山西太岳山4种不同植被类型为对象,研究其土壤微生物量碳、氮(MBC、MBN)含量以及土壤和凋落物养分含量的变化特征,并利用通径分析模型,探讨土壤和凋落物养分含量对土壤微生物量的效应.结果显示:MBC、MBN和土壤有机碳(SOC)、全氮(TN)含量随土层深度加深逐渐减小.各层土壤SOC、TN含量均表现为草甸>华北落叶松人工纯林>华北落叶松白桦混交林>灌木林;MBC和MBN含量分别为143-900 mg/kg和22-155 mg/kg,两者均在草甸和华北落叶松白桦混交林中显著高于华北落叶松人工纯林和灌木林;土壤微生物量碳氮比在A(0-10 cm)、B(10-20 cm)两层的变化范围为6-8,在C(20-30 cm)、D(30-40 cm)两层的变化范围为4-10.土壤微生物熵在华北落叶松白桦混交林和灌木林下达到较高水平,碳熵和氮熵的变化范围分别为0.6%-2.8%和1.4%-5.4%.通径分析结果表明,土壤理化性质、凋落物养分含量和土壤微生物量之间存在不同程度的相关性,凋落物N含量是影响土壤微生物量的直接因素之一.总体来说,不同植被类型对土壤微生物量有重要的影响,落叶松人工纯林和草甸对碳库的作用更大,有利于养分的积累.(图5表8参43)

In order to understand the effect of vegetation type on soil microbial biomass, this paper investigated the variation of soil microbial biomass with the soil and litter nutrient content in Mt. Taiyue, Shanxi, China. We measured soil microbial biomass and analyzed its correlation with soil physical-chemical properties and litter nutrient content by using path analysis model for Larix principis-rupprechtii Mayr. artificial？pure forest （PF）, Larch-Betula platyphylla？Suk. mixed forests （MF）, shrubbery （S） and meadow （M）. The results showed that： （1） the content of soil microbial biomass C and N, soil organic carbon （SOC） and total nitrogen （TN） gradually decreased with the soil depth. （2） The content of SOC, TN, MBC and MBN of each layer decreased in the order of M 〉 PF 〉 MF 〉 S. The content of MBC and MBN in M and MF were significantly higher than those in PF and S. （3） The range of MBC/MBN was 6-8 in layers A and B and 4-10 in layers C and D. （4） The soil microbial entropy in MF and S were significantly higher than those in PF and M. （5） Path analysis showed certain degree of correlation between soil microbial biomass and soil physical-chemical properties or litter nutrient content. （6） The vegetation type had an effect on soil microbial biomass, with PF and M the most beneficial to soil carbon contents.