水保所知识产出(1956---)知识库

土壤水力性质是影响水分运动、溶质运移以及流域水文模型模拟的重要参数。近年来，黄土高原实施的退耕还
林（草）工程、治沟造地工程等重大生态工程，影响了该区域的地形地貌、土壤水力性质等。深入研究流域尺度土壤容
重（ Bulk Density， BD）与饱和导水率（Ks）的动态变化特征，对于理解重大生态工程影响下的水文过程演变规律具有
重要意义。本研究以黄土高原重大生态工程影响的典型小流域为对象，采用 80 m×80 m 的网格布点（89 个样点），分别
于 2016 年 9 月（夏末）、11 月（初冬）和 2017 年 3 月（初春）采集土壤表层（0～5 cm）环刀样品，分析 BD 和 Ks 的动
态分布特征及其影响因素。结果表明：BD 在 0.93～1.61 g/cm 3 之间变动，Ks 介于 0.01～7.30 cm/min；BD 呈弱变异性，
变异系数（Coefficient of Variation，CV）为 10%，而 Ks 呈强变异性（CV=166%）。坡面 BD 显著小于沟底（P<0.05），而
Ks 则显著大于沟底（P<0.05）。坡面林地和草地 BD 表现出显著的季节性差异（P<0.05），而 Ks 在林地、灌木和草地之间
均表现出显著的季节性差异（P<0.05）。地形对流域内的土壤水力参数分布有显著影响，外界环境（温度）变化是决定
BD 和 Ks 呈季节性动态变化的重要因素。多因素方差分析表明土地利用类型对 BD 与 Ks 均有显著影响；采样时间对 Ks
有显著影响，对 BD 无显著影响。相关结果可为揭示重大生态工程区小流域土壤水力参数的动态变化规律及其主控因素
提供数据支撑和理论参考，有助于小流域水文过程的模型模拟研究与精细调控。

Soil bulk density and saturated hydraulic conductivity are two important hydraulic parameters of soil, and thereby
highly affect water holding capacity of soil, infiltration, runoff formation, and soil erosion. There are great topographical
changes on the Loess Plateau of China, as the projects of Grain for Green and Gully Land Consolidation have been largely
implemented in recent years. It is essential to understanding the temporal change of soil bulk density and saturated hydraulic
conductivity, and their response to the intensive land restoration projects for the ecological management on Chinese Loess
Plateau. Taking Gutun watershed as the research area, the objective of this study was to investigate the temporal variation of
soil bulk density and saturated hydraulic conductivity and their controlling factors in the intensive land restoration area, where
the projects of Grain for Green and the Gully Land Consolidation were widely implemented. The sampling point of an 80 m ×
80 m grid, and totally with 89 sampling sites were selected, in order to ensure that the sampling sites were uniformly
distributed and represented all types of land use in the watershed. Measurements of soil bulk density and saturated hydraulic
conductivity were conducted on undisturbed soil samples at each site taken from the surface soil layers (0-5 cm) on three
periods in September and November 2016 and March 2017 at Gutun watershed on the Chinese Loess Plateau. The results
showed that the soil bulk density ranged from 0.93 to 1.61 g/cm 3 , while the saturated hydraulic conductivity was from 0.01 to
7.30 cm/min (for all sites). The soil bulk density displayed a weak variability (Coefficient of Variation (CV) was 10%) among
different seasons, while the saturated hydraulic conductivity indicated a strong variability (CV=166%, for all sites). The soil
bulk density on slope was significantly smaller than that in gully (P<0.05), while the saturated hydraulic conductivity on slope
was significantly larger than that in gully (P<0.05). The soil bulk density increased from September to November 2016, and
then decreased from November 2016 to March 2017, whereas the saturated hydraulic conductivity showed an adverse trend
among the three measurements. The soil bulk density under forest and grassland showed a significantly seasonal variation,
whereas the saturated hydraulic conductivity displayed a significantly seasonal variation under all land use types. Topography
(elevation) played an important role in determining the soil bulk density and saturated hydraulic conductivity in the area, where
the projects of intensive land restoration implemented. External environment (temperature) was the controlling factor that
determined the temporal change of soil bulk density and saturated hydraulic conductivity. Multivariate analysis revealed that
the land use posed a significant impact on the soil bulk density and saturated hydraulic conductivity. The duration and the
interaction of land use had significant impact on saturated hydraulic conductivity, not for soil bulk density. The results
demonstrate that it is necessary to consider the temporal variation of soil bulk density and saturated hydraulic conductivity and
their affecting factors, when modelling and predicting the relevant soil hydraulic processes. This finding can also provide a
deep insight to the related eco-hydrology processes in the implemented areas of intensive land restoration.