Wang Bing, Wen Fenxiang, Wu Jiangtao, Wang Xiaojun, Hu Yani
College of Environmental Science and Resources, Shanxi University, Taiyuan, China.
Library, Hebei University of Science and Technology, Shijiazhuang, China.
PLoS One. 2014 Oct 14;9(10):e109546. doi: 10.1371/journal.pone.0109546. eCollection 2014.
Characterization of soil water content (SWC) profiles at catchment scale has profound implications for understanding hydrological processes of the terrestrial water cycle, thereby contributing to sustainable water management and ecological restoration in arid and semi-arid regions. This study described the vertical profiles of SWC at the small catchment scale on the hilly and gully Loess Plateau in Northeast China, and evaluated the influences of selected environmental factors (land-use type, topography and landform) on average SWC within 300 cm depth. Soils were sampled from 101 points across a small catchment before and after the rainy season. Cluster analysis showed that soil profiles with high-level SWC in a stable trend (from top to bottom) were most commonly present in the catchment, especially in the gully related to terrace. Woodland soil profiles had low-level SWC with vertical variations in a descending or stable trend. Most abandoned farmland and grassland soil profiles had medium-level SWC with vertical variations in varying trends. No soil profiles had low-level SWC with vertical variations in an ascending trend. Multi-regression analysis showed that average SWC was significantly affected by land-use type in different soil layers (0-20, 20-160, and 160-300 cm), generally in descending order of terrace, abandoned farmland, grassland, and woodland. There was a significant negative correlation between average SWC and gradient along the whole profile (P<0.05). Landform significantly affected SWC in the surface soil layer (0-20 cm) before the rainy season but throughout the whole profile after the rainy season, with lower levels on the ridge than in the gully. Altitude only strongly affected SWC after the rainy season. The results indicated that land-use type, gradient, landform, and altitude should be considered in spatial SWC estimation and sustainable water management in these small catchments on the Loess Plateau as well as in other complex terrains with similar settings.
流域尺度土壤含水量（SWC）剖面特征对于理解陆地水循环的水文过程具有深远意义，从而有助于干旱和半干旱地区的可持续水资源管理和生态恢复。本研究描述了中国东北丘陵沟壑区黄土高原小流域尺度SWC的垂直剖面，并评估了选定环境因素（土地利用类型、地形和地貌）对300厘米深度内平均SWC的影响。在雨季前后从小流域的101个点采集土壤样本。聚类分析表明，小流域中最常见的是SWC水平稳定（从上到下）的土壤剖面，特别是在与梯田相关的沟壑中。林地土壤剖面的SWC水平较低，垂直变化呈下降或稳定趋势。大多数弃耕地和草地土壤剖面的SWC水平中等，垂直变化趋势各异。没有土壤剖面的SWC水平较低且垂直变化呈上升趋势。多元回归分析表明，不同土壤层（0 - 20、20 - 160和160 - 300厘米）的平均SWC受土地利用类型的显著影响，一般按梯田、弃耕地、草地和林地的顺序递减。整个剖面的平均SWC与坡度之间存在显著负相关（P<0.05）。地貌在雨季前显著影响表层土壤层（0 - 20厘米）的SWC，但在雨季后影响整个剖面，山脊处的SWC水平低于沟壑。海拔仅在雨季后对SWC有强烈影响。结果表明，在黄土高原这些小流域以及其他具有类似环境的复杂地形的空间SWC估算和可持续水资源管理中，应考虑土地利用类型、坡度、地貌和海拔。
