太行山区典型坡地产流过程坡面分异特征及其成因

Soils in gneiss area of Taihang Mountain are thin and always have high infiltration rate. Soil properties have high variance along the elevation gradient. The distribution and variation of runoff generation process and its causes are still unclear, which limit the further understanding of soil hydrological processes in Taihang Mountain. In this study, rainfall simulation, field point monitoring, and indoor and outdoor experiments methods will be used to study the runoff generation processes in 15 runoff plots (10 m2) which will be built on 5 different slope positions (top, upper, middle, lower, and bottom of the slope). Temporal dynamic of soil moisture content, vertical variation of soil hydraulic conductivity and its anisotropy along soil profile, runoff generation processes of surface and different soil layers, and the relationship between runoff and soil moisture and saturated hydraulic conductivity will be studied. Based on the soil properties, topographical factors, meteorological factors and vegetation, the variation of runoff process along the slope and its influencing factors will be further analyzed. This study will provide further understanding of soil hydrological processes in gneiss area of Taihang Mountain. In addition, it can also provide scientific basis for the increasing of soil water storage and the formulating of policies.

太行山片麻岩区土壤浅薄、入渗速率快且土壤性质沿海拔梯度变异大，坡地产流过程在坡面上的分异规律及其成因仍不明确，限制了对太行山区土壤水文过程的深入了解。本研究拟以太行山区典型坡地为研究对象，在上坡、中上坡、中坡、中下坡及下坡布设15个径流微小区（10 m2），基于模拟降雨方法，结合原位定点监测及室内外实验，研究太行山区典型坡地土壤水分动态特征；揭示土壤饱和导水率及其各向异性在土壤剖面上的垂直分异规律；弄清地表径流及不同层次的壤中流产流过程，并分析其坡面分异规律；探讨产流过程与土壤水分动态及饱和导水率各向异性的内在关系，结合土壤理化性质（质地、容重、孔隙度等）、地形因子（海拔、坡度等）、气象因子（雨强、雨量等）及植被状况（覆盖度、枯落物等）等因素，深入分析产流过程坡面分异的成因。该研究可加深对太行山片麻岩区土壤水文过程的认知。同时，为山区土壤水源涵养功能的提升及相关政策的制定提供科学依据。

太行山片麻岩区土壤浅薄、入渗速率快且土壤性质沿海拔梯度变异大，坡地产流过程在坡面上的分异规律及其成因仍不明确，限制了对太行山区土壤水文过程的深入了解。本研究以太行山区典型坡地为研究对象，通过在上坡、中坡及下坡布设径流小区，利用模拟降雨方法，结合原位定点监测及室内外实验，研究了太行山区典型坡地土壤水分动态特征；揭示了土壤饱和导水率及其各向异性在土壤剖面上的垂直分异规律；厘清了地表径流及不同层次的壤中流产流过程及其坡面分异特征。结果显示，上坡位土壤含水量显著小于中坡和下坡，中坡和下坡之间差异不显著；3个坡位均表现出表层土壤含水量显著小于其他层次的趋势；降水后，上坡土壤含水量响应最为迅速，而下坡响应时间最长。土壤垂直饱和导水率表现为上坡位显著大于中坡位和下坡位，而土壤水平饱和导水率在3个坡位差异不大；土壤饱和导水率各向异性比多小于1，且随土壤深度增加，在上坡呈增加趋势，而中坡和下坡呈现出波动趋势且变化规律不明显。下坡位受土壤厚度大的影响，总体产流较小，上坡土壤浅薄且孔隙度大，产流较多。不同坡位土壤产流层次不同。上坡各层次均是重要的产流层次；中坡20cm和30cm是重要的产流层次，下坡表层和40cm为重要的产流层次。对比不同产流层次和土壤剖面属性垂直变异规律，发现上层土壤水平饱和导水率和本层土壤垂直饱和导水率之比为控制本层土壤产流的主要因素。该研究可加深对太行山片麻岩区土壤水文过程的认知。同时，为山区土壤水源涵养功能的提升及相关政策的制定提供科学依据。