【作者】 王伟；

【导师】 解建仓； 王涛；

【作者基本信息】 西安理工大学 ， 水文学及水资源， 2010， 硕士

【摘要】 土地资源紧缺是制约当前我国经济发展的主要问题之一,盐碱地作为一种贫瘠的土地,随着社会的进步,其治理技术取得了长足的进步现已成为珍贵的后备土地资源。以往的盐碱地治理多是以水洗盐、以水排盐为主,这对于水资源短缺的落后地区实施起来困难重重,本文结合“卤泊滩”盐碱地治理模式,通过室内模拟试验提出蓄水条件下过渡层理论,这对于干旱缺水地区盐碱地治理有十分重要的意义。本文在查阅了有关国内外文献的基础上,对于土壤水盐运动研究的现状进行了综述,并结合陕西省国土资源厅项目：“陕西卤泊滩盐碱地综合治理和谐生态模式研究与实践”的具体内容,采用室内试验为主的方法对大水压盐时以及蓄水条件下土壤过渡层的盐分运移规律进行了分析研究,并且应用HYDRUS-1D模型模拟蒸发条件下土壤非饱和层及过渡层水分的动态平衡以及盐分的对流—弥散作用。研究取得的主要成果如下：(1)本文通过模拟灌水,确定了在整个观测期内垂直入渗距离与入渗时间的关系。在水分入渗的过程中,最大湿润距离为128cm,入渗过程大致可分为渗润、渗漏、渗透几个阶段。得出垂直湿润距离与时间呈乘幂函数关系,H=3.698T0.344,R2=0.9243。(2)经过20天的模拟灌水试验,发现灌水对土壤表层盐分的冲洗作用效果明显。从试验数据来看在入渗条件下随着时间的延长,土壤各层全盐量均有不同程度的下降,整个变化过程根据土壤全盐量变化的程度大致可分为0～-45cm快速减少层、-45～-90cm缓慢减少层、-90～-120cm缓慢上升层。(3)通过近2个月的室内模拟试验,发现在蓄水条件下存在10～20cm的过渡层,蓄水20cm时过渡层出现在-120cm、-105cm观测孔,厚度约15cm左右,蓄水40cm时出现在-90cm、-75cm观测孔,厚度约16cm左右,蓄水70cm时出现在-75cm、-60cm观测孔,厚度约21cm左右。(4)试验确定20cm、40cm、70cm三个蓄水位,初始含盐量包括各层均质和底层含量高两种情况。从三组对比试验来看,在不同蓄水条件下土壤各层全盐量变化趋势基本一致,饱和层基本稳定,过渡层减少,非饱和层有不同程度的上升。但无论饱和层盐分含量高低,在整个试验期内均处于相对稳定状态,过渡层对下层高含盐的隔离作用显著。(5)利用HYDRUS-1D软件,对蒸发条件下不同蓄水位的土壤含水率和盐分含量进行了模拟,从而对试验结果进行验证,通过比较模拟值和实测值发现两者差异较小,对模拟值和实测值进行绝对误差计算,大多数值在11%以下,只有少数值偏差较大达到22%左右,模拟结果基本满足精度要求。(6)在蓄水作用下,通过循环压盐理论可改变垂直方向上土壤盐分的分布情况,过渡层理论作为“改排为蓄”治理模式中重要理论之一,它系统的解释了盐分在垂直方向上的去向,认为通过过渡层可实现对土壤饱和层盐分的隔离作用。更多还原

【Abstract】 The lack of land resources is one of main problems which restriction our county’s economic development at present.Saline land used as a kind of barren soil, with social progress, it become a precious reserved land resources when treatment technology had acquired ansiderable progress.The previcus treatment mainly with salt washing and salt exclusion in water, it is very difficulty for backward areas where water shortage.This paper combines "LuBoTan" gavemance model, through laboratory simulation test, put forward transition layer theory.It is very impotant for alklaing soil in drought and scare water areas.Based on data from recent study articles, study actuality home and abroad summarize on soil water and salt movement, combined with project of resources department of Shannxi Provice:"The reseaech on harmonious ecological comprehensive treatment model of saline land in LuBoTan, Shannxi Provice". Focus on water and salt movement under the condition of inundation to restrain salt content and water-reserving of soil transition layer with laboratory test method,application HYDRUS-1D model simulation under the condition of water dynamic balance and salt advection-dispersion of soil unsaturated region and soil soil transition layer in evaporation conditions,results were obtained as follows:(1) This text passes by simulation of irrigation.paper records the relation between vertical infiltration distance and infiltration time during the observation period.In the water infiltration process, the last wetting front distance is 128cm. According to the change of wetting front distance,there are three stages:percolation,leakage,infiltration. The vertical infiltration distance and time is a power function, H=3.698T0.344, R2=0.9243.(2) Through simulation irrigation for 20 days,found that infiltration can significantly washing the salt of soil surface. As the passage of time in infilation condition,the total salt content of each soil layer had decreased in of different degree.Based on the variation degree of total salt content,can divided into three layers:0～-45cm rapid decrease layer、-45～-90cm slow reduce layer、-90～-120cm rose slowly layer. (3) By laboratory simulation test in 3 months, found there is a transition layer (10-20cm) in water-reserving condition, transition layer present to-120cm and-105cm peephole when water storage 20cm, the thickness is 15cm; present to-90cm and-75cm peephole when water storage 40cm, the thickness is 16cm; present to-75cm and-60cm peephole when water storage 70cm, the thickness is 20cm.(4) The experiments assurance 3 pool level (20cm、40cm、70cm), the soil initial salt content including inundation to restrain salt content and upper and lower uniformly.Through 3 contrast test, the total salt content of each soil layer of variation trends are similar in differend water-reserving condition,it is stable in saturated layer, it is reduce in transition layer,it is rose in unsaturated region. But whether the content of salt in is high or low in saturated layer,is in relative steady state during the test period.Transition layer have a remarkable isolated effects for salt in lower layer.(5) Soil water content and salt content are simulated using the software of HYDRUS-1D in evaporation conditions when water storage,in order to verification testing result, the average error between simulating data and measuring data is less than 11%,individual is 22%. And the conclusions of the numerical simulation are coherent to the experiment data approximately.(6) Under storge water conditions, through cycle-press the salt can change the distribution of the soil salt in vertical,transition layer as a important theory for change drainage to impoundment model of saline land, it can explain the fate of the soil salt in vertical, transition layer can isolate salt for saturated layer.更多还原