摘要
降雨特征和坡度是影响土壤入渗过程的重要因素,在植被恢复过程中,其对土壤入渗特征的影响可能会有所不同。选取黄土丘陵区6个坡度(5°,10°,15°,20°,25°和30°)的撂荒草地(2年)径流小区(5 m×20 m),观测自然降雨条件下(共计34场降雨,产流11场)植被生长旺期(7—9月)土壤入渗特征,研究降雨过程参数(降雨量、平均雨强、降雨历时和I30)、坡度和植被盖度对坡面入渗特征的影响。结果表明:(1)11场产流降雨不同坡度土壤入渗量总体变化范围为6.58~70.91 mm,入渗补给系数为0.83~1.00,入渗率为0.22~19.35 mm/h;(2)土壤入渗量随降雨量呈线性增加(R^2=0.99,p<0.01),入渗补给系数随I30呈指数降低(R^2=0.91,p<0.01),平均入渗率随降雨强度呈线性增加(R^2=0.71,p<0.01),随降雨历时呈幂函数降低(R^2=0.99,p<0.05);(3)坡度增大使得径流位移增长,导致入渗量、入渗补给系数和平均入渗率整体随坡度增大而呈幂函数增加,但当坡度>25°时,因径流势能沿坡面方向分量增加,径流流速加快,上述入渗特征参数略有降低;(4)由于降雨量在植被生长周期内呈下降趋势,很大程度上导致植被对入渗特征的影响受控于降雨量,土壤入渗量表现出随着植被盖度的增加呈幂函数显著下降的趋势。总体而言,降雨特征和坡度是影响土壤入渗的主要因素,且土壤入渗特征参数可表示为降雨过程参数和坡度的综合幂函数方程;在入渗补给系数较高的情况下,植被覆盖对土壤入渗特征的影响减弱。研究结果对于坡面尺度降雨径流调控机制和生态水文过程研究具有重要意义。
Rainfall characteristics and slope gradients are important factors that affect soil infiltration process, and their effects on soil infiltration characteristics may be different during the process of vegetation restoration. To discuss the effects of rainfall process parameters (rainfall, mean rainfall intensity, rainfall duration and I30), inclination of slopes and vegetation coverage on the infiltration characteristics, six runoff plots of two-years abandoned grassland with the slope gradients of 5°, 10°, 15°, 20°, 25°, and 30° were selected in the hilly region of the Loess Plateau, and their soil infiltration characteristics were observed in the peak period of vegetation growth (July to September) under natural rainfall (34 rainfall event and 11 rainfall-generated runoff). The results indicated that: (1) For the 11 runoff-producing rainfall under different slope gradients, the variations of soil infiltration amount was ranged from 6.58 to 70.91 mm, the infiltration supplement coefficient was ranged from 0.83 to 1.00, and the infiltration rate was ranged from 0.22 to 19.35 mm/h;(2) The amount of soil infiltration increased linearly with rainfall capacity (R^2=0.99, p<0.01) and the infiltration supplement coefficient decreased exponentially with I30 (R^2=0.91, p<0.01). While for the average infiltration rate, it was increased linearly with rainfall intensity (R^2=0.71, p<0.01) and decreased exponentially with rainfall duration (R^2=0.99, p<0.05);(3) The increase in slope gradient extended the runoff displacement, resulting in the exponential increase in the infiltration volume, the infiltration supplement coefficient, and the average infiltration rate. However, when the slope gradient exceeded 25°, the component of runoff potential energy increased along the slope direction, the runoff velocity speeds up, and the above-mentioned infiltration characteristic parameters decrease slightly. (4) The amount of rainfall showed a downward trend during vegetation growth cycle, which to some largely extent manipulate
作者
肖婧
王兵
XIAO Jing;WANG Bing(Research Center of Soil and Water Conservation and Ecological Environment,Ministry of Education and Chinese Academy of Sciences,Yangling,Shaanxi 712100;State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau,Northwest A&F University,Yangling,Shaanxi 712100;University of Chinese Academy of Sciences,Beijing 100049)
出处
《水土保持学报》
CSCD
北大核心
2019年第6期136-142,共7页
Journal of Soil and Water Conservation
基金
国家自然科学基金面上项目“基于RUSLE模型的黄土高原草地植被覆盖因子(41771555)
国家自然科学基金重点项目“退耕驱动近地表特性变化对侵蚀过程的影响及其动力机制”(41530858)
国家重点研发计划项目“黄河流域生态系统变化的水资源效应与作用机理”(2016YFC0501603)
国家重点研发计划项目“黄土丘陵沟壑区植被功能提升与山地果园管理关键技术及示范”(2016YFC0501703)
关键词
雨强
草地盖度
坡度
土壤入渗
rainfall intensity
grassland coverage
slope gradient
soil infiltration
