摘要
土壤前期含水量与降雨是坡面产流的主要影响因素。该研究基于超渗产流基本原理,通过引入土壤前期含水量与降雨2个指标,最终推导出基于土壤前期含水量-降雨耦合关系的坡面产流所需临界值公式。通过该公式结合土壤水分实测值对陕北黄土区吴起县典型植被群落干旱年、正常年和湿润年的产流临界降雨值进行模拟计算与分析。结果表明:1)陕北黄土坡面湿润年产流所需临界降雨量与干旱年和正常年存在显著差异,湿润年产流所需降雨量较少且油松湿润年理论产流值最低,仅需5. 60 mm;干旱年与正常年产流所需临界降雨量则不存在显著差异,但干旱年产流所需降雨量较大。2)不同植被类型产流所需最低降雨量不同,其中油松林地产流所需临界降雨量最小,即油松林地较易产流,沙棘纯林产流所需降雨量最大,即沙棘林地较难产流;且2种林地产流所需降雨量存在显著差异。土壤前期含水量与降雨二者耦合关系及其与坡面产流临界阈值的研究,对该区域预防土壤侵蚀带来的危害和水土资源高效利用具有重要意义。
[Background] Antecedent soil moisture and rainfall（ ASAM） are the main influencing factors on runoff occurring in a loess slope at northern Shaanxi. There have been many models for the coupling relationship between runoff and factors of antecedent soil moisture and rainfall,but they are based on regression analysis,their practicality and universality are limited,especially on the forecast of runoff erosion. [Methods]Based on the basic principle of runoff occurring under excess infiltration and introduced 2 indicators of antecedent soil moisture and rainfall,the model for the rainfall threshold while runoff occurs for a loess slope was deduced based on the coupling relationship between antecedent soil moisture and rainfall. Then according to this model and combined with the measured soil moisture,therainfall threshold while runoff occurs was simulated,calculated and analyzed during the drought year,normal year and wet year in the typical vegetation community in the Wuqi county of northern Shaanxi loess region. [Results]1） Rainfall thresholds while runoff occurred differed significantly between wet years and dry years as well as normal years in the loess slope of northern Shaanxi. The required rainfall for runoff occurring in wet years was little and the theoretical rainfall for runoff occurring was the lowest at5. 6 mm. There were no significant difference in rainfall thresholds for runoff occurring between dry years and normal years,but rainfall required in dry years for runoff occurring was large. 2） The minimum rainfall for runoff occurring at different vegetation types was different,while the rainfall threshold for runoff occurring in Pinus tabulaeformis forest land was the least,i. e.,the runoff in the P. tabulaeformis forest land easily occurred. The rainfall for runoff occurring in Hippophae rhamnoides forest land was the most,i. e.,it was difficult for H. rhamnoides forest land to have runoff occurring. There was a significant difference in the rainfall thresholds for runoff occurring between these two vegetation types. 3）When vegetation and other topographical conditions were the same,the lower the rainfall intensity was,the longer the time required for runoff occurring was; the more the amount of rainfall loss was,the longer the time required for runoff occurring was. 4） When the surface soil of a slope had high saturated water content and the antecedent soil moisture content was small,the field rainfall required for runoff occurring was high; when the soil density on a soil slope was large,the rainfall required for runoff occurring was also large. When the depth of soil infiltration on the slope surface was shallow,the amount of rainfall required for runoff occurring was also small. [Conclusions] Studying the coupling relationship between the ASMA and the critical rainfall threshold of loess slope runoff is of great significance to prevent soil erosion and to effectively utilize water and soil resources in this area.
作者
艾宁
刘广亮
朱清科
刘广全
强方方
AI Ning;LIU Guangliang;ZHU Qingke;LIU Guangquan;QIANG Fangfang(College of Life Science,Yan＇an University,716000,Yan＇an,Shaanxi,China;China Institute of Water Resources and Hydropower Research,100044,Beijing,China;Wuqi County Project Management Office of Returning Farmland to Forest,717600,Wuqi,Shaanxi,China;School of Soil and Water Conservation,Beijing Forestry University,100083,Beijing,China)
出处
《中国水土保持科学》
CSCD
北大核心
2018年第5期23-29,共7页
Science of Soil and Water Conservation
基金
"十三五"国家重点研发计划(2016YFC0501602
2016YFC0501705)
延安大学博士科研启动项目(YDBK2016-12)
关键词
土壤前期含水量
降雨
产流临界降雨值
黄土坡面
antecedent soil moisture
rainfall
rainfall threshold while runoff occurs
loess slope
