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题名: 北京城区与郊区土壤碳氮循环的差异研究
作者: 陈帅
学位类别: 硕士
答辩日期: 2011
授予单位: 中国科学院研究生院
授予地点: 北京
导师: 王效科
关键词: 城市土壤 ; urban soil ; 土壤有机碳 ; soil organic carbon ; 微生物群落特征 ; microbial community function ; 无机氮 ; inorganic nitrogen ; 氮循环 ; nitrogen cycle
其他题名: The differences in soil carbon and nitrogen cycles between urban and suburban in Beijing
中文摘要:       城市化不但对社会经济发展具有重大影响,而且会对城市生态系统产生很大影响。土壤作为城市生态系统中重要的组成部分,也会受到城市化的影响,发生一系列的变化,包括土壤碳氮循环规律的变化。本研究在北京城区与郊区选择三种常见的人工林(油松、侧柏、毛白杨)土壤开展对比研究,分析了土壤有机碳库、微生物量碳、微生物群落功能多样性和不同季节的氮循环特征的城郊差异及其影响因素。主要的结果如下: 1.北京城区林地土壤pH、全N与郊区差异不大,而土壤容重和C/N比都显著高于郊区。 2.林地土壤有机碳城区与郊区的差异不显著。郊区林地土壤微生物量碳含量(367.29 mg kg-1)显著高于城区(294.23 mg kg-1)。郊区林地土壤微生物活性高于城区。林地土壤微生物多样性和均匀度城郊差异不显著,但树种间存在一定的差异。说明城市化过程对城市土壤微生物量以及微生物群落的结构和功能有一定影响,且这种影响存在树种间差异。 3.北京城区与郊区林地土壤硝态氮和氨态氮含量均有明显的季节动态,夏季显著高于春季和秋季。三个季节城区林地土壤硝态氮含量均显著高于郊区(春季28.41 mg kg-1和19.66 mg kg-1;夏季99.35 mg kg-1和59.51 mg kg-1;秋季9.61 mg kg-1和5.63 mg kg-1)。城区林地土壤净潜在矿化速率高于郊区,但差异未达到显著水平,而反硝化潜势城区高于郊区,且差异达到极显著性水平。夏、秋两季,城区和郊区的林地土壤硝态氮含量存在树种间差异,夏季城区的林地土壤的净潜在矿化和硝化也呈现出树种间的差异(p < 0.05)。 4.影响城区与郊区林地土壤无机氮库的环境因子存在差异,城区林地土壤无机氮库的变化主要与土壤有机碳和容重相关,而郊区主要与土壤水分相关。
英文摘要:       Urbanization not only has big impact on the socioeconomic development, it also influences the urban ecosystem significantly. Urban soil as the most important component of urban ecosystem, also experiences certain change under urbanization process, including the change of carbon and nitrogen cycle in urban soil. However little is known about the ecological effects of urbanization on carbon and nitrogen cycle in urban soil. Research on carbon and nitrogen cycle of urban soil is significantly important for learning regional biogeochemical cycle well. In this study, we chose three forest types, specifically Pinus tabulaeformis, Platycladus orientalis and Populus tomentosa, in the urban and suburban regions of Beijing, to compare the differences of organic carbon, microbial biomass carbon, microbial community function and nitrogen cycle characteristic, and analyze the principal soil factor that influence urban and suburban nitrogen cycle. The main conclusions were as followed. 1. Some urban soil character changed during the urbanization with human disturbance. pH and total nitrogen showed no significant difference in urban and suburban, while density bulk and C/N in urban were significant higher than that in suburban. 2. According to the results, we cannot see significant difference of organic carbon in urban and suburban. And microbial biomass carbon of soil in suburban forests is significantly larger than urban forests (suburban 367.29 mg kg-1, urban 294.23 mg kg-1). For the same forest type, microbial activity is higher in suburban regions with insignificant differences. Further analysis reveals that there are no considerable differences of microbial diversity and homogeneity in urban and suburban areas; however, comparatively, differences between varied forest types are more noticeable. 3. Our results indicated that soil nitrate nitrogen and ammonia nitrogen have obvious seasonal fluctuations; and the inorganic nitrogen concentration in summer was significantly higher than that in spring and autumn. In addition, as to all seasons, the concentration of nitrate nitrogen in urban areas was considerably higher than that in suburban areas for all three seasons(spring 28.41 mg kg-1 /19.66 mg kg-1; summer 99.35 mg kg-1 /59.51 mg kg-1; autumn 9.61 mg kg-1 / 5.63 mg kg-1). The rate of net potential mineralization trends to increase towards the urban center, while denitrification potential rate in urban is significantly higher than suburban. Moreover, in summer and autumn, the concentration of nitrate nitrogen for different forest types displayed significant differences. 4.Further regression analysis showed that the soil factors influencing the inorganic nitrogen and nitrogen cycle in urban and suburban regions are obviously different. Specifically, inorganic nitrogen in urban center was primarily influenced by TOC and bulk density; whereas that in suburban was affected by soil water content. This research indicated that urbanization significantly increases the soil nitrate accumulation and accelerates the rate of its mineralization in urban regions. It also revealed the variances of the impacts among different urban tree species for this response and regulation capacity.
内容类型: 学位论文
URI标识: http://ir.rcees.ac.cn/handle/311016/35074
Appears in Collections:城市与区域生态国家重点实验室_学位论文

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Recommended Citation:
陈帅. 北京城区与郊区土壤碳氮循环的差异研究[D]. 北京. 中国科学院研究生院. 2011.
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