氮添加对帽儿山地区六树种人工林土壤微生物生物量及群落结构的影响

发布时间：2018-01-03 15:05

本文关键词：氮添加对帽儿山地区六树种人工林土壤微生物生物量及群落结构的影响　出处：《东北林业大学》2016年硕士论文　论文类型：学位论文

【摘要】：土壤微生物是森林生态系统中重要的组成部分,对管理土壤的养分收支、调节土壤的理化平衡、清理土壤的有毒物质、辅助植物的养分吸收等发挥重要的作用。氮被认为是温带森林土壤生态系统净初级生产力的限制性养分因素,对土壤生态系统的物质和能量变化产生影响。因此,研究氮添加对土壤微生物含量及群落结构的影响对于了解森林土壤生态系统针对环境变化的响应有十分重要的意义。本文应用磷脂脂肪酸技术,探讨了短期施氮肥对东北主要造林树种红松(Pinus koraiensis)、云杉(Picea koraiensis)、落叶松(Larix gmelinii)、黄菠萝(Phellodendron amurensis)、水曲柳(Fraxinus mandschurica)、胡桃楸(Juglans mandschurica)土壤微生物含量及群落结构的影响,同时结合土壤理化性质分析,探讨了影响土壤微生物群落的因素,得到以下结论：(1)氮添加显著提高了6树种人工林土壤铵态氮和硝态氮含量,且对硝态氮含量影响远超过铵态氮。同时,氮添加导致6树种人工林土壤pH显著下降,说明施肥导致6树种人工林产生强烈的硝化作用。另外氮添加对土壤全碳和全氮含量并未产生显著影响,说明短期氮添加不能造成土壤碳氮格局的改变。此外,受氮添加影响,6树种人工林全磷含量显著降低,原因可能是土壤有效氮增加导致树木对磷的需求量增加。(2)6树种人工林土壤微生物生物量碳氮随季节变化显著,且均表现为春季夏季秋季的变化规律。氮添加导致土壤微生物生物量碳氮在各季节均显著降低,但并不改变其季节动态格局,说明氮添加对土壤微生物产生明显影响。(3)通过磷脂脂肪酸分析结果得知,氮添加对土壤微生物含量产生影响,导致6树种人工林土壤微生物总量和细菌含量的显著下降,且对针叶树种的影响普遍大于阔叶树种。另外氮添加对针叶树真菌的含量产生显著影响,但对阔叶树真菌的含量影响不显著。氮添加对6树种人工林土壤放线菌含量均不构成显著影响。(4)氮添加显著改变了6树种人工林土壤微生物群落结构,导致土壤真菌／细菌比的显著下降,下降的主要原因是真菌含量的下降。另外氮添加改变了细菌群落结构,导致革兰氏阳性菌与革兰氏阴性菌的比例降低,说明氮添加缓解了环境条件对革兰氏阴性菌的限制。(5)将土壤微生物含量与土壤理化性质进行相关性分析,结果表明土壤pH值是影响微生物含量的最重要因素,氮添加引起的土壤有效氮含量增加并不直接影响微生物的活性和含量,但是,氮添加引起的土壤pH值降低和增加的土壤酸化对微生物的影响是不能忽视的。
[Abstract]:Soil microorganism is an important component of forest ecosystem, the soil nutrient budget management, physical and chemical balance of soil, soil clean up toxic substances, auxiliary plant nutrient absorption play an important role. Nitrogen is the limiting nutrient factors of net primary productivity in temperate forest soil ecosystem, effects on soil the ecological system of substance and energy changes. Therefore, study on the effects of nitrogen addition on soil microbial community structure and content for the understanding of forest ecosystem in response to environmental change has important significance. This paper by phospholipid fatty acid, discusses the pine fertilizer on the main afforestation tree species in short Northeast (Pinus koraiensis), spruce (Picea koraiensis), larch (Larix gmelinii), yellow pineapple (Phellodendron amurensis), Fraxinus mandshurica (Fraxinus mandschurica), Juglans mandshurica (Juglan S mandschurica) and the content of soil microbial community structure, combined with analysis of soil physicochemical properties, discussed the influence factors of soil microbial community, get the following conclusions: (1) nitrogen addition significantly increased 6 species of plantation soil ammonium nitrogen and nitrate nitrogen content, and the influence on the nitrate content of more than ammonium nitrogen is added. At the same time, resulting in 6 species of plantation soil pH decreased significantly, indicating fertilization resulted in 6 tree plantation had strong nitrification. In addition nitrogen addition on soil total carbon and total nitrogen content did not have a significant impact, that short period of nitrogen addition can cause changes in the pattern of soil carbon and nitrogen. In addition, n effect of adding, the total phosphorus content of 6 species of plantation was significantly reduced, the reason may be led to an increase in soil available nitrogen phosphorus increased demand for trees. (2) 6 species of artificial forest soil microbial biomass carbon and nitrogen with seasonal changes significantly , and showed that variation of spring and summer autumn. Nitrogen addition resulted in both soil microbial biomass carbon and nitrogen decreased significantly in each season, but did not change its seasonal pattern, that nitrogen addition has significant effects on soil microorganisms. (3) by phospholipid fatty acid analysis showed that nitrogen addition effect on microorganism the content of soil, resulting in a significant decrease of 6 tree species in plantation soil microbial biomass and bacterial content, and the influence on coniferous trees larger than broad-leaved tree species. In addition to add nitrogen content on conifer fungi have a significant impact, but the impact on the content of broadleaf tree fungus was not significant. Nitrogen addition on Soil 6 species plantations actinomycetes content does not constitute a significant impact. (4) nitrogen addition significantly changed the 6 tree species of plantation, soil microbial community structure, resulting in a significant decrease of soil fungi / bacteria ratio, the main reason for the decline Is the content of fungi decreased. In addition, nitrogen addition changed the bacterial community structure, resulting in gram positive bacteria and gram negative bacteria decreased the proportion that nitrogen addition to ease the limitation of environmental conditions on Gram negative bacteria (5). The content of soil microbial and soil physicochemical properties in the correlation analysis, the results showed that soil pH value is the most important factors affecting the microbial content, nitrogen content of soil available nitrogen increase does not directly affect the content and activity of microorganisms, but nitrogen added soil pH value caused by decreasing and increasing the effect of soil acidification on microbes can't be ignored.

【学位授予单位】：东北林业大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：S714.3

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