【作者】 马玉霞；

【导师】 宋孝玉；

【作者基本信息】 西安理工大学 ， 水文学及水资源， 2009， 硕士

【摘要】 黄土高塬沟壑区是水土流失严重的区域,生态环境十分脆弱。南小河沟流域是在该区域设定的关于水土保持工作原型观测的小流域。在生物措施方面,需通过合理规划、整地工程、植树种草和配套集水蓄水设施的完善,来实现良好生态环境的恢复和建设。由此利用黄土高塬沟壑区已建立的不同土地利用的径流小区资料,分析其土壤水分和浅层土壤水资源的状况,具有十分重要的意义。在已有研究的基础上,主要致力于下述4个方面的研究：(1)研究区降雨和土壤特征分析；(2)降雨、地形、整地方式和集水面处理对土壤水分的影响；(3)不同土地利用下的土壤水分效应；(4)建立不同土地利用与土壤水资源的耦合模型,用于模拟和预测土壤水资源的变化情况。以期在经济发展需求和土壤水分环境允许的条件下,为种植业结构调整提供理论指导。获得的主要研究结果如下：1.利用Eagleson (1978b)的分析方法,计算南小河沟流域降雨参数的旬气象值。并由实测水分运动参数数据拟合流域57个测点的VG模型参数。2.分析各土层间的相关关系及其对降雨的响应表明：对于较上层土壤(如20cm处),随土层的增深,其与该上层的土壤水分的相关系数依次减小(0.540>0.394>0.390>0.322),正体现了上层土壤水分对下层土壤水分的影响,距离越远,对其影响越小。0-100cm的平均含水量与20cm、40cm、60cm的土壤含水量的相关关系最密切,也是由于此土层之间水分较稳定,变异系数小。有效降雨量与10cm、20cm处有相关关系,由于该土层直接受到降雨的影响,而在60cm以下土层,与有效降雨量和表层土壤无线性相关关系。3.分析方位、坡度和坡位对土壤水分的影响表明：土壤含水量的大小整体上呈现阴沟无林区最大,依次为阴沟有林区、阴山坡无林区、阳沟无林区、阴山坡有林区、阳山坡有林区；沟道土壤含水率最大,其次为塬面,坡面,变异系数的大小依次为坡面、塬面、沟道；坡度越大土壤水分条件越差,同时农地较林地的土壤水分条件差。在大坡面上,土壤含水率沿不同高差的坡面呈不规则锯齿状向上延伸,而且有减小趋势。4.分析不同土地利用的土壤水分的垂向分布和浅层土壤水资源的变化表明：坡面荒草地土壤含水量最多,依次为坡面人工草地、坡面林地、塬面农地。在垂向上,土壤水分变化活跃的土层也是根系分布密集区,林草根系发育较深。5.以土壤水动力学理论为指导,运用一维饱和—非饱和带水分运移方程,对的土壤水分运移规律进行数值模拟,并利用Hydrus-1D软件进行模型的实现。通过四种土地利用(塬面农地、坡面林地、坡面人工草地和坡面荒草地)的径流小区的次降雨的资料,率定土壤的特征参数,使模型可用于模拟降雨后的土壤水分再分布。同时选取三种典型水平年的汛期降雨资料,模拟四种不同土地利用的土壤水资源的动态变化。根据实测数据,验证该模型能较好的模拟各种地类土壤水分的动态变化及土壤水资源量。更多还原

【Abstract】 Loess gully plateau region is the serious area having serious soil erosion,where the ecological environment is very fragile. Nanxiahegou basin which established the water and soil conservation prototype in this area. On living beings measure, it’s on the need to achieve the restoration and construction of a good ecological environment, by reasonable planing, preparation projects, planting trees and grasses and perfecting corollary facilities of water collection and storage. Therefore it’s very important that utilizing the runoff districte dates of different land use in loess gully plateau region to analyse the states of soil moisture and shallow layer of soil water resource.On the basis of having studies, this research is mainly devoted to four researches as following:(1) Rainfall and soil characteristic; (2) The impact on soil moisture of rainfall, topography, land preparation modes and the catchment surface disposal;(3) The soil moisture effect under different land uses; (4) Seting up the coupling model between the soil water resource and land ues which can simulate and predict the soil water resource. In the condition of economic development demand and soil moisture environment permission, it can offer the effective analysis means for planting’s structural adjustment. The main results of study are following:1. Utilizing the analytical method of Eagleson (1978b), it calculated the meteorological value of ten days of nanxiaohegou basin rainfall parameter. Fitted and examined soil moisture parameter in 57 measuring points of basin, clicked by Li Yajuan’s data of surveying.2. Analyse the relevant relation and response to the rainfall of each soil layer. To the top soil layer position (such as 20cm place), the downward correlation coefficient is reduced (0.540＞0.394>0.390＞0.322) sequentially,which reflect the impact on lower floor soil moisture of the upper soil moisture.The longer the distance, the smaller the influence. The average soil water content of 0～100cm and the water contents of soil of 20cm,40cm,60cm are in the close relations, because the moisture between this soil layers have steady relations, and the coefficient of variation is small. There are relevant relations with effective rainfall of 10cm, 20cm place, because this soil layer is influenced by rainfall directly. The soil layers under 60cm are not linear relevant relation with effective rainfall and top layer soil.3. This paper analyzed the impact on soil moisture of the position, slope and slope location. In position aspect, soil water content suquences are:cloacae non-forest regin, cloacae forest regin,shady slop non-forest regin,positive channel non-forest regin, shady slop forest regin, sunny slop forest regin. On the topography, The water content in ditch is higher than that in yuanmian and domatic, the size of the coefficient of variation is successively domatic, Yuan, ditch. In domatic, soil moisture in big slope terms is bad. Synchronously,farmland and forest land moisture terms are poor relatively at the same time. In heavy domatic, soil moisture content of domatic extend upwards along different discrepancy to take the form of irregular sawtooth in elevation and the decreasing tendency.4. Analyse the change to distributing of soil moistureand soil water resource of shallow layer. the soil water content of waste-grassland in slope is the maximum,and the soil water content of grassland in slope, forest land in slope and farmland in yuanmian is decreases successively.In vertical direction,the soil layer of the root system in the compact district is the soil moisture changes active, and the forest grass root system development is relatively deep.5. The numerical simulation for the regulation of the mosture movement using one dimension movement square in none saturation zone under the guidelization of soil hydrodynamic theories utilize Hydrus-1D to carry on the realization. Through already having simulation of individual rainfall in surface flow district(including farmland in yuanmian、grassland in slope、forest land in slope、waste-grassland in slope), waste-grassland in slope、adjust the hydraulic parameters of the soil.And simulate the dynamic change of the soil water resource under four kinds of different land use. According to the datas of surveying, it proved that the model is rational to be effective.更多还原