松嫩草地土壤酶活性对模拟氮沉降组分变化的响应

发布时间：2018-06-11 11:47

本文选题：氮沉降 + 氮组分　；参考：《东北师范大学》2017年硕士论文

【摘要】：随着社会经济的发展,对化石燃料和肥料的大量消耗导致大气氮沉降速率逐年增加并成为全球气候变化的重要组成部分。从1980s到2000s,氮沉降量呈现逐年增长的趋势,研究数据显示增加量大约为0.41KgNha-1yr-1,且发达地区要高于偏远地区。除了氮沉降量发生巨大变化外,氮沉降组分的变化也成为科研聚焦点和人们关注的热点。氮沉降组分中的无机氮成分,如NO3-和NH4+的生态环境影响已有大量研究,而对有机氮成分(胺、烃、氨基酸等)及其生态效应却了解较少。本实验以东北地区的松嫩盐碱化草地为研究对象,结合野外实地模拟和室内培养实验,研究了模拟氮沉降量和组分变化对土壤酶活性的影响。本研究共设置两个氮肥梯度:10 g N m-2 yr-1和20 g N m-2 yr-1;在每个氮肥水平上设计四种不同有机氮(尿素和甘氨酸)和无机氮(硝酸铵)的比例,分别为TIN(100%无机氮);LON(70%无机氮、30%有机氮);MON(30%无机氮、70%有机氮);HON(10%无机氮、90%有机氮)。除此之外设置一个无氮添加的对照处理。野外实验部分在隶属于东北师范大学的松嫩草地生态研究站开展,采取原位取土盆栽方法,土柱取自盐碱草地。室内控制实验在学校的人工培养室内进行,利用培养箱对盐碱土进行培养。实验得到的主要结果有:(1)野外原位实验,大部分酶(α-葡糖苷酶、碱性磷酸酶、亮氨酸氨基肽酶和乙酰葡糖胺糖苷酶等)在添加有机氮的处理下酶活性显著高于只添加无机氮的处理,而大多数酶在MON处理时表现出最大酶活性。(2)氮添加水平对于土壤全氮和微生物碳有显著作用,对土壤有机碳和土壤pH值没有显著影响;不同有机氮无机氮比例对四种土壤因子作用效果显著,除了土壤有机碳外,对于其它三种土壤环境因子,氮添加水平和氮比例二者均存在交互作用。这些研究结果表明,氮肥添加水平和不同氮肥组分比例是微生物活性和酶活性的重要影响因子。(3)相关性分析结果显示,大多数酶与土壤环境因子均有显著相关关系,拟合方程的结果多数为一元二次方程。(4)植被密度和地上生物量对于氮添加水平有显著响应,在四个植被指标方面,施氮水平和氮比例二者之间均不存在交互作用。对于物种数目来说,它们在不同有机、无机氮比例之间均不存在显著性差异,植被高度在10 g N添加条件下,CK(对照)处理和TIN、LON、HON处理之间存在显著差异。(5)室内培养实验对照处理下的酶活性一般呈现先升高再下降然后又增长接着降低的趋势,或者出现先增长后降低的变化过程。室内培养实验氮处理条件下水解酶的活性多数在培养45天左右出现最大值。本研究结果显示,氮添加水平和氮比例显著改变松嫩草地微生物生物量和酶活性。现有探究性实验在关注氮沉降速率对生态系统影响的同时,也应关注氮沉降组分变化及其相关生态学效应。本研究结果有助于理解全球气候变化背景下,尤其是氮沉降量和组分改变,松嫩草地关键资源生物地球化学循环的响应过程和趋势。
[Abstract]:With the development of society and economy, the large consumption of fossil fuel and fertilizer has led to the increase of atmospheric nitrogen deposition rate and become an important part of global climate change. From 1980s to 2000s, the nitrogen deposition has been increasing year by year. The research data show that the increase is about 0.41KgNha-1yr-1, and the developed areas should be higher than the remote area. In addition to the great changes in nitrogen deposition, the changes in nitrogen deposition components have also become the focus of scientific research and the focus of attention. There has been a lot of research on the inorganic nitrogen components in the nitrogen deposition components, such as NO3- and NH4+, and less on the organic nitrogen components (amines, hydrocarbons, amidic acid and so on) and their ecological effects. In the northeastern region of Songnen saline alkali grassland, the effects of simulated nitrogen deposition and component changes on soil enzyme activity were studied in field simulation and indoor culture experiments. Two nitrogen fertilizer gradients were set up in this study: 10 g N m-2 yr-1 and 20 g N m-2 yr-1, and four different organic nitrogen (urea) were designed at each nitrogen level. The proportion of the glycine and the inorganic nitrogen (ammonium nitrate) are TIN (100% inorganic nitrogen), LON (70% inorganic nitrogen, 30% organic nitrogen), MON (30% inorganic nitrogen, 70% organic nitrogen), HON (10% inorganic nitrogen, 90% organic nitrogen). Besides this, a nitrogen free control treatment is set up. The field experiment part is in the Songnen grassland ecological research station of Northeast Normal University. The main results were: (1) the main results were as follows: (1) field in situ experiments, most of the enzymes (alpha glucosidase, alkaline phosphatase, leucine aminopeptidase and acetylglucosamine) The enzyme activity under the addition of organic nitrogen was significantly higher than that of only inorganic nitrogen, while most of the enzymes showed the maximum enzyme activity in MON treatment. (2) the nitrogen addition level had significant effect on soil nitrogen and microbial carbon, and had no significant influence on soil organic carbon and soil pH value; the ratio of organic nitrogen to inorganic nitrogen was four. The effect of soil factors was significant. Besides soil organic carbon, there was interaction between the two other three soil environmental factors, nitrogen addition level and nitrogen ratio. These results showed that the nitrogen addition level and the proportion of different nitrogen fertilizer components were important factors of microbial activity and enzyme activity. (3) correlation analysis results. The results showed that most of the enzymes had significant correlation with soil environmental factors, and the results of the fitting equation were mostly two times equation. (4) the vegetation density and aboveground biomass have significant response to the nitrogen addition level. There is no interaction between the nitrogen application level and the nitrogen ratio in the four vegetation indices. For the number of species, the number of species is not interactive. There was no significant difference between the different organic and inorganic nitrogen ratios. There was a significant difference between the vegetation height and the TIN, LON, HON treatment under the condition of 10 g N addition. (5) the enzyme activity in the laboratory culture experiment was generally higher and then decreased then then decreased and then decreased, or appeared first. The results of this study showed that the nitrogen addition level and nitrogen ratio significantly changed the microbial biomass and enzyme activity in the Songnen grassland. The existing exploratory experiment was concerned with the effects of nitrogen deposition rate on the ecosystem. At the same time, we should also pay attention to the variation of nitrogen sedimentation components and their related ecological effects. The results of this study will help to understand the response process and trend of the biogeochemical cycle of the key resources of the Songnen grassland, especially in the background of global climate change, especially the change of nitrogen deposition and components.
【学位授予单位】：东北师范大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S812.2

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