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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)
Taking the four different vegetation types in Taiyue Mountain of Shanxi as an example, the changes of soil microbial biomass carbon and nitrogen (MBC) and nutrient contents in soil and litter were studied. Through the path analysis model, the effects of soil and litter nutrient (MBC), MBN and soil organic carbon (SOC) and total nitrogen (TN) content decreased with the deepening of soil depth.The SOC and TN contents of all soil layers showed as follows: meadow> Larix principis-rupprechtii stands> mixed stands of Larix principis-rupprechtii-Betula platyphylla> shrubs with MBC and MBN of 143-900 mg / kg and 22-155 mg / kg respectively, both in the mixed stands of Betula platyphylla and Larix principis-rupprechtii Was significantly higher than that of Larix principis-rupprechtii pure and shrub forest. The soil microbial biomass C and N ratios varied from 6 to 8 in A (0-10 cm) and B (10-20 cm) -30 cm) and D (30-40 cm). The soil microbial entropy reached a higher level under mixed stands of Betula platyphylla, Betula platyphylla and Betula platyphylla, and the ranges of carbon entropy and nitrogen entropy were respectively From 0.6% to 2.8% and from 1.4% to 5.4%, respectively.The results of path analysis showed that there was no significant difference in soil physical and chemical properties, litter nutrient content and soil microbial biomass There are different degrees of correlation between litter N content is one of the direct factors affecting soil microbial biomass.In general, different types of vegetation have an important impact on soil microbial biomass, Larch artificial meadow and meadow carbon pool A greater role, is conducive to the accumulation of nutrients. (Figure 5 Table 8 Reference 43)