隔离降雨对米槠天然林土壤呼吸及微生物群落的影响

发布时间：2018-07-14 14:22

【摘要】：本研究样地位于福建大武夷山常绿阔叶林野外定位观测站三明观测点米槠天然林,通过设置隔离30%降雨(T1)、隔离60%降雨(T2)以及没有隔离降雨的对照(CK),进行定位研究。着重从土壤微生物群落结构变化的角度,探讨隔离降雨对米槠天然林土壤呼吸的影响。通过室内设置10%WHC(Water Holding Capacity,土壤持水量)、30%WHC、60%WHC、80%WHC土壤含水量试验,以及30%WHC-80%WHC干湿交替试验,揭示含水量变化对土壤有机碳矿化的内在机理,为阐明隔离降雨对土壤呼吸的影响提供有利的补充说明。结果表明：(1)不同程度隔离降雨土壤呼吸的月动态变化基本一致,土壤呼吸的年平均速率表现为T2T1CK,但三个处理之间土壤呼吸速率及土壤呼吸年通量差异均不显著。(2)隔离降雨对土壤微生物群落的影响主要集中于0-10 cm土层,对10-20 cm土层微生物生物量和群落结构均无较大影响。主成分分析表明,2013年11月0-10 cm土层中,隔离30%降雨水平土壤微生物群落,与隔离60%降雨水平及对照的微生物群落存在较大差异,而2014年4月和2014年9月,0-10cm三个处理间土壤微生物群落差异不大。对0-10 cm土层的17种磷脂脂肪酸进行因子分析发现,隔离降雨对土壤微生物群落影响大小表现为,革兰氏阳性菌放线菌丛枝菌根真菌革兰氏阴性菌真菌。(3)室内模拟试验表明,土壤有机碳累积矿化量随着土壤含水量的增加而增加,4个水分处理水平均对土壤革兰氏阳性菌产生较大影响。干湿交替湿润期C02累积量明显高于干旱期C02累积量,并且随着交替次数的增加,CO2累积值大小差异越明显。因子分析表明干湿交替对土壤放线菌和革兰氏阳性菌的影响较大,而对土壤丛枝菌根真菌、革兰氏阴性菌和土壤真菌的影响不大。
[Abstract]:The sample land was located in Sanming natural forest of Sanming observation site of evergreen broadleaved forest in Dawyishan, Fujian Province. The location was studied by setting up isolation of 30% rainfall (T1), 60% rainfall (T2) and CK without isolated rainfall. The effect of rainfall isolation on soil respiration in Castanopsis carlesii natural forest was studied from the point of view of soil microbial community structure change. By setting up 10WHC (Water holding capacity), 30 WHC-80WHC soil moisture test, and 30WHC-80WHC dry and wet alternating test, the inherent mechanism of soil organic carbon mineralization caused by water content change is revealed. It provides a favorable supplementary explanation to clarify the effect of rainfall isolation on soil respiration. The results show that: (1) the monthly dynamic changes of rainfall soil respiration in different degrees are basically the same; The annual average rate of soil respiration was T _ 2T _ 1 CK, but there was no significant difference in soil respiration rate and soil respiration flux among the three treatments. (2) the effect of rainfall isolation on soil microbial community was mainly concentrated in 0-10 cm soil layer. There was no significant effect on microbial biomass and community structure in 10-20 cm soil layer. Principal component analysis (PCA) showed that the soil microbial communities isolated at 30% rainfall level in 0-10 cm soil layer in November 2013 were significantly different from those in 60% rainfall isolation level and control. However, there was no significant difference in soil microbial communities between April 2014 and September 2014. By factor analysis of 17 phospholipid fatty acids in 0-10 cm soil layer, it was found that the effect of isolated rainfall on soil microbial community was as follows: Gram-positive actinomycetes, arbuscular mycorrhizal fungi, gram-negative fungi. The accumulation and mineralization of soil organic carbon increased with the increase of soil water content, and all the four water treatments had a great effect on Gram-positive bacteria in soil. The accumulation of CO2 in dry and wet alternate wetting period was significantly higher than that in drought period, and the difference of CO2 accumulation value was more obvious with the increase of alternating times. Factor analysis showed that dry and wet alternation had a great effect on soil actinomycetes and Gram-positive bacteria, but had little effect on soil arbuscular mycorrhizal fungi, Gram-negative fungi and soil fungi.
【学位授予单位】：福建师范大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S714.3

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