重金属污染区土壤水热参数相关性研究

发布时间：2018-09-01 12:01

【摘要】：土壤质地、入渗率、含水率和热导率作为土壤的基本物理性质,对上述参数进行监测是农业研究中的一项基础工作,其研究意义表现在土壤有机质积累、化学反应速率、节水灌溉和水资源的高效利用等众多方面;土壤水热参数的相互关系对土壤水热耦合过程和溶质运移亦具有重要意义。本课题研究开发了快速识别土壤质地的计算机软件;并以呈贡区壤土和东川矿区粉壤土不同土地利用类型地块为研究区,以上述地块中的供试土样为研究对象,对土壤理化性质和水分入渗过程进行了实地测定;继而对含水率与热导率的相关性进行分析。在研究过程中得到的主要成果如下:(1)研究区土壤入渗性能较好,表现为稳定入渗率较快、累积入渗量较大。试验中盘径对入渗结果影响不显著;相同时间内东川粉壤土累积入渗量大于呈贡壤土;相同地块中负压水头越高稳定入渗率越小,且累积入渗量越少;不同土地利用类型对土壤饱和导水率影响较大,表现为灌木地草地农耕地裸地。(2)供试地块土壤含水率及热导率存在强烈的空间相关性,试验中随机因素引起的空间变异程度较低。浅层土壤水分空间分布中边界效应表现明显;深层土壤中孔隙的连通性对土壤水分空间分布贡献较大;不同深度土层含水率的差异是由蒸发强度、耕作活动所引起;土壤含水率主导了热导率的空间分布,使得二者的空间分布特征相似性较高。(3)不同深度土层及不同土地利用类型条件下,土壤含水率与热导率回归结果表现为正线性相关,且含水率为17%～22%时线性关系较高;根据空间序列的谱分析拟合结果得到热导率在含水率序列上呈现长程负相关。上述研究成果旨在为精准农业田间管理提供帮助;为当地节水灌溉和水分高效利用提供理论参考;为各地区类似基础研究提供方法借鉴。
[Abstract]:Soil texture, infiltration rate, moisture content and thermal conductivity are the basic physical properties of soil. Monitoring the above parameters is a basic work in agricultural research. The significance of the study is the accumulation of soil organic matter and the rate of chemical reaction. Water saving irrigation and efficient utilization of water resources are also of great significance to the coupling process of soil water and heat and the transport of solute. In this paper, a computer software for quick identification of soil texture is developed, and the different land use types of loam soil and silt loam in Dongchuan mining area are taken as the research areas, and the samples of the tested soil in the above-mentioned plots are taken as the research objects. The physical and chemical properties of soil and the process of water infiltration were measured, and the correlation between moisture content and thermal conductivity was analyzed. The main results obtained during the study are as follows: (1) the soil infiltration performance in the study area is better, which shows that the stable infiltration rate is faster and the cumulative infiltration amount is larger. At the same time, the cumulative infiltration amount of Dongchuan silty loam is larger than that of Chenggong loam, the higher the negative pressure head in the same plot, the smaller the stable infiltration rate, and the less the cumulative infiltration. Different land use types have great influence on soil saturated water conductivity, which is shown as shrub grassland farmland bare land. (2) there is strong spatial correlation between soil moisture content and thermal conductivity of the plots. The degree of spatial variation caused by random factors was low. The boundary effect is obvious in the spatial distribution of shallow soil water, the connectivity of pores in deep soil contributes greatly to the spatial distribution of soil moisture, the difference of soil moisture content in different depth is caused by evaporation intensity and tillage activity. Soil moisture content dominates the spatial distribution of thermal conductivity, which makes the spatial distribution characteristics similar. (3) under different soil depth and different land use types, the regression results of soil moisture content and thermal conductivity show a positive linear correlation. The linear relationship between water content and water content is 17 ~ 220.According to the spectral analysis of spatial series, the thermal conductivity shows a long range negative correlation on water content series. The research results mentioned above are aimed at providing help for field management of precision agriculture, theoretical reference for local water-saving irrigation and water efficient use, and methods for similar basic research in various regions.
【学位授予单位】：昆明理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S152.7

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