不同环境条件下黄土土壤无机呼吸特征及其预测模型

发布时间：2018-05-21 18:07

本文选题：土壤无机呼吸 + 温度　；参考：《新疆大学》2015年硕士论文

【摘要】：全球土壤是一个巨大的碳库,是大气CO2重要的来源。据估计,全球土壤每年排放C量高达68×1015g/a[1]。由于大气CO2是引起全球变化的重要温室气体。因此,研究土壤呼吸对于探讨全球变化及其影响,具有十分重要的意义。土壤呼吸是陆地生态系统碳循环的关键环节,是陆地生态系统将碳素以CO2形式归还给大气的主要途径。它对环境因子变化的响应,在很大程度上决定着全球气候变化与碳循环之间的反馈关系。土壤呼吸作为全球碳循环的重要组成部分,占整个陆地生态系统呼吸的60%-90%,是调控全球碳循环和气候变化的关键,其对全球碳循环的重要作用已经逐渐得到广泛关注。分析土壤呼吸过程的环境因子,并且确定其对土壤呼吸速率的影响作用,对于碳循环的研究具有重要意义。土壤呼吸包括两方面,一是土壤有机呼吸即植物根呼吸、土壤微生物呼吸以及土壤动物呼吸。二是土壤无机呼吸即非生物学过程(含碳物质的化学氧化作用)。传统定义上,认为土壤有机呼吸占主导地位,但最近研究发现,土壤无机呼吸的作用不容小觑。世界干旱土壤占全球陆地总面积的40%,其中大量的土壤无机碳在全球碳储存、缓解大气CO2浓度升高过程中具有重要作用,在全球碳循环过程中的贡献日益显著。中国黄土高原地处干旱、半干旱区,富含碳酸盐,无机碳库是碳库的主要形式,故探究我国黄土土壤无机呼吸具有重要的意义。本文以典型的黄土分布区兰州市红古区所采的黄土为实验对象,以测定模拟不同温度(-16℃、4℃、20℃、30℃)、不同降雨量(0.0 mm、2.5mm、5.0mm、15.0mm)以及不同碳酸钙含量(14%、17%、20%、23%)条件下的黄土土壤无机呼吸速率以及空气、土壤温湿度变化和土壤基本性质数据为基础,利用相关分析法,探讨黄土土壤无机呼吸速率的变化特征及其与空气温、湿度和土壤温、湿度等影响因素之间的关系。并利用回归分析法分别建立了不同温度、降雨量以及碳酸钙条件下的黄土土壤无机呼吸速率线性及非线性预测模型,为探讨黄土在全球土壤CO2通量变化中的作用提供依据。主要研究成果与结论:(1)一般来说,低温条件下(-16℃),温度为影响黄土土壤无机呼吸的主要影响因素。中温条件下(4℃、20℃),黄土土壤无机呼吸速率受温度和湿度的共同作用。高温条件下(30℃),影响土壤无机呼吸的主要因素是空气湿度。(2)无降雨的对照组中,黄土土壤无机呼吸速率受土壤、空气温湿度的共同影响较大。小雨降雨过程中,呼吸速率主要受空气湿度影响,降雨过后,则受土壤温湿度的共同作用。中雨条件下,雨中、雨后呼吸速率分别受土壤温度和空气湿度的影响较大。大雨情况下,降雨中土壤无机呼吸速率受土壤温、湿度和空气湿度三因素共同影响,雨后则受土壤温度的作用最大。在本实验温度条件下,雨量越大如中雨和大雨,则正呼吸越强,而少量的水分(小雨情况)下,黄土土壤无机呼吸速率更易出现负值,故推测湿度是影响土壤呼吸可能为负值的关键因子。(3)黄土土壤中碳酸钙含量为14%的条件下,土壤无机呼吸与空气温度和土壤温度相关性均较好。碳酸钙含量增加到17%时,呼吸速率与空气温、湿度和土壤温度的相关性均达极显著,而到碳酸钙达20%、23%时,其土壤无机呼吸速率与空气温、湿度和土壤温、湿度均达极显著相关。这说明碳酸钙含量越高,其土壤无机呼吸数量越易受温、湿度的共同影响。同时随着碳酸钙含量的增加,呼吸速率呈减小的趋势,即土壤呼吸过程中吸收的二氧化碳越多,黄土越易呈“碳汇”。
[Abstract]:Global soil is a huge carbon pool and an important source of atmospheric CO2. It is estimated that global soil emissions of C are as high as 68 * 1015g/a[1]. a year, because atmospheric CO2 is an important greenhouse gas that causes global change. Therefore, it is of great significance to study soil respiration to explore global changes and its effects. Soil respiration is a terrestrial ecology. The key link in the system carbon cycle is the main way for land ecosystem to return carbon to the atmosphere in the form of CO2. Its response to the changes in environmental factors determines the feedback relationship between global climate change and carbon cycle to a large extent. Soil respiration is an important part of the global carbon cycle, accounting for the entire terrestrial ecosystem. The 60%-90% of respiration is the key to the global carbon cycle and climate change, and its important role in the global carbon cycle has been gradually paid attention to. It is of great significance to analyze the environmental factors of soil respiration and to determine its effect on soil respiration rate, which is of great significance to the research of carbon cycle. Soil respiration includes two aspects. Organic respiration of soil is plant root respiration, soil microbial respiration and soil animal respiration. Two is soil inorganic respiration or non biological process (chemical oxidation of carbon material). Traditionally, soil organic respiration is dominant, but recent studies have found that the role of soil inorganic respiration should not be underestimated. Soil accounts for 40% of the total land area of the world, of which a large amount of soil inorganic carbon plays an important role in the global carbon storage, alleviates the increase of atmospheric CO2 concentration, and contributes increasingly to the global carbon cycle. The Loess Plateau in China is located in arid, semi-arid, rich in carbonates and inorganic carbon pools as the main form of carbon storage. The soil inorganic respiration of the Loess Soil in the country is of great significance. In this paper, the loess soil collected in the Lanzhou city of Lanzhou, which is typical of the Loess distribution area, is used to determine the different temperatures (-16, 4, 20, 30), and the different rainfall (0 mm, 2.5mm, 5.0mm, 15.0mm) and the different calcium carbonate content (14%, 17%, 20%, 23%). Based on the data of air, air, air, soil temperature and humidity and soil basic properties, the relationship between the change characteristics of soil inorganic respiration rate and the influence factors such as air temperature, humidity, soil temperature and humidity are discussed by correlation analysis method. The different temperatures and rainfall are established by regression analysis method. The linear and nonlinear prediction model of inorganic respiration rate of loess soil under the condition of calcium carbonate can provide a basis for discussing the effect of loess on the change of CO2 flux in the global soil. The main research results and conclusions are as follows: (1) generally, under low temperature (-16), temperature is the main influence factor of soil inorganic respiration in loess soil. Under the medium temperature condition (4 C, 20 C), the inorganic respiration rate of loess soil is affected by temperature and humidity. Under high temperature (30 degrees C), the main factor affecting the soil inorganic respiration is air humidity. (2) in the control group without rainfall, the soil inorganic respiration rate is affected by the soil and the air temperature and humidity. In the process of rain and rain, the rate of respiration is main. In the rain condition, the respiration rate of the soil is influenced by the soil temperature and the air humidity respectively. In the heavy rain, the soil inorganic respiration rate is affected by three factors, the soil temperature, the humidity and the air humidity, and the soil temperature after the rain. Under the temperature condition of this experiment, the greater the rainfall, such as rain and rain, the stronger the positive respiration, and the less water (small rain), the soil inorganic respiration rate is more liable to negative. Therefore, the humidity is the key factor affecting the soil respiration may be negative. (3) the content of calcium carbonate in the loess soil is 14%. The correlation between soil inorganic respiration and air temperature and soil temperature was better. When calcium carbonate content increased to 17%, the correlation between respiration rate and air temperature, humidity and soil temperature was very significant. When calcium carbonate reached 20%, 23%, the soil inorganic respiration rate was significantly correlated with air temperature, humidity and soil temperature and humidity. The higher the content of calcium carbonate, the more the soil inorganic respiration is affected by temperature and humidity, and with the increase of calcium carbonate content, the rate of respiration is decreasing, that is, the more carbon dioxide absorbed in the soil respiration process, the more easily the loess is "carbon sink".
【学位授予单位】：新疆大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S154

【参考文献】