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本文以山西太岳山3个林龄(18、35和51年生)华北落叶松林为对象,研究其土壤微生物生物量、土壤真菌群落结构多样性特征,并利用通径分析,探讨土壤和凋落物养分含量对土壤微生物的影响。结果表明:随着华北落叶松林年龄的增加,土壤微生物生物量碳逐渐增加,微生物生物量碳占其与可溶性有机碳之和的比例也逐渐增加;土壤微生物生物量碳/氮比在51年生华北落叶松林中最大(13),约为其他两个林龄华北落叶松林的1.6倍;土壤微生物碳熵在35年生华北落叶松林中最低(1.5%),在18年生华北落叶松林中最高(2.8%)。土壤微生物生物量氮、真菌Shannon指数、土壤和凋落物碳/氮比在不同林龄华北落叶松林中的变化趋势均为35年生>18年生>51年生。通径分析结果表明,真菌群落结构多样性对土壤微生物生物量碳有较大的直接作用,凋落物自身化学组成对土壤微生物生物量氮有显著影响,土壤碳/氮比和微生物生物量碳/氮比是调控真菌群落结构多样性的直接因素。总的来说,35年生华北落叶松林的土壤有机碳活性最小,土壤碳库稳定性较好,养分状况优于另外两个林龄华北落叶松林。
In this study, the Larix principis-rupprechtii (Eighteen, 35th and 51-year-old) forests in Taiyue Mountain of Shanxi Province were used to study the characteristics of soil microbial biomass and community fungal community diversity. Path analysis was conducted to investigate the effects of soil and litter nutrient Effect of content on soil microbe. The results showed that as the age of Larix principis-rupprechtii increased, the soil microbial biomass carbon increased gradually, and the ratio of microbial biomass carbon to soluble organic carbon increased gradually. The soil microbial biomass C / N ratio was 51% Larix (13) was the largest in Larix principis-rupprechtii, which was about 1.6 times of that in the other two stands. The soil microbial carbon entropy was the lowest (1.5%) in the 35-year-old Larix principis-rupprechtii forest and the highest (2.8% ). Soil microbial biomass nitrogen, fungi Shannon index, soil and litter carbon / nitrogen ratio in the different age stands of Larix principis-rupprechtii were 35 years> 18 years> 51 years. Path analysis showed that the diversity of fungal communities had a greater direct effect on soil microbial biomass carbon. The chemical composition of litterfall had a significant effect on soil microbial biomass nitrogen. The soil C / N ratio and microbial biomass carbon / Nitrogen ratio is the direct factor controlling the diversity of fungal community structure. In general, the soil organic carbon of the 35-year-old Larix principis-rupprechtii forest had the lowest soil organic carbon pool, the better soil carbon pool, and the better nutrient status than the other two Larix principis-rupprechtii forest.