表层土壤结构对红壤坡耕地产流及产沙过程的影响  

Effects of Top Soil Structure on Runoff and Sediment Yield of Red Soil Slope Cropland

作　　者：张紫薇 赵文俊 李奇 马一淳 田亮 杨广勇 李忠武[1] 刘窑军 ZHANG Ziwei;ZHAO Wenjun;LI Qi;MA Yichun;TIAN Liang;YANG Guangyong;LI Zhongwu;LIU Yaojun(School of Geographical Sciences,Hunan Normal University,Changsha 410081,China;Research Center for Soil and Water Conservation,Huazhong Agricultural University,Wuhan 430070,China)

机构地区：[1]湖南师范大学地理科学学院,长沙410081 [2]华中农业大学水土保持研究中心,武汉430070

出　　处：《土壤学报》2024年第2期434-444,共11页Acta Pedologica Sinica

基　　金：国家自然科学基金项目(41877084,41501287);湖南省自然科学基金项目(2022JJ30389);湖南省大学生创新创业训练计划项目(S202110542121)资助。

摘　　要：针对南方红壤区坡耕地水土流失严重与表层结构退化的现状,采用室内模拟降雨的方法,分析表层土壤结构和雨强对降雨再分配、坡面产流及产沙过程的影响。结果表明:(1)表层土壤结构显著改变降雨的再分配过程,深耕作层可以降低地表径流比例,增加壤中流比例,60和90 mm·h^(-1)雨强下,随耕作层深度增加,地表径流平均比例依次为70.5%,62.9%和56.8%,壤中流平均比例依次提升为7.1%,12.3%和18.1%;(2)土壤流失率随雨强增加而增大,90 mm·h^(-1)雨强下土壤流失率为60 mm·h^(-1)雨强下的4.4倍,土壤流失率随耕作层深度增加而显著减小,依次为36.8、21.1和13.1 g·m^(-2) min^(-1);(3)雨强和表层土壤结构显著影响坡面侵蚀形态的演变,随耕作深度增加坡面侵蚀由细沟侵蚀逐渐转变为面蚀。表层土壤结构显著改变坡耕地降雨-径流关系和侵蚀过程,合理增加耕作层深度,对降低地表侵蚀、促进土壤水分的深层下渗、增加土壤深层持水量具有积极作用。【Objective】Based on the current situation and severity of soil and water loss,it is vital to investigate the nature and extent of surface structure degradation of slope farmland and long-duration rainfall characteristics in the red soil region of southern China.【Method】The method of long-term rainfall simulation were adopted to test the effects of topsoil structure and rainfall intensity on rainfall redistribution,runoff and sediment yield.In this paper,three rainfall intensities,30 mm·h^(-1),60 mm·h^(-1) and 90 mm·h^(-1),respectively,and three cultivation depths,10 cm,20 cm and 30 cm,respectively,were set to study the effects of tillage lager depth and rainfall intensity on surface flow,subsurface flow,soil loss rate and erosion pattern.【Result】The results showed that:(1)The topsoil structure significantly changed the redistribution process of runoff.Higher tillage layer depth can mitigate the effects of rainfall intensity,reduce the surface flow coefficient,and increase subsurface flow.Under the condition of 60 mm·h^(-1) and 90 mm·h^(-1) rainfall intensity,the average surface flow coefficient decreased in the sequence of 70.5%(TLD10 cm),62.9%(TLD20 cm),and 56.8%(TLD30 cm),and the average subsurface flow ratio increased in the sequence of 7.1%(TLD10 cm),12.3%(TLD20 cm),and 18.1%(TLD30 cm).(2)The soil loss rate was enhanced with the increase in rainfall intensity but decreased with the depth of the tillage layer.Under 60 mm·h^(-1) rainfall intensity,the peak soil loss rate of 10 cm,20 cm and 30 cm tillage depth were 35.1,25.6 and 20.5 g·m^(-2) min^(-1),respectively.For 90 mm·h^(-1) rainfall intensity,these values were 68.7,55.8 and 48.4 g·m^(-2) min^(-1),respectively.(3)Rainfall intensity and topsoil structure significantly affect the final slope erosion forms.With the increase of tillage layer depth,the erosion degree decreased significantly.Under the condition of 30 mm·h^(-1) rainfall intensity,the surface of the soil was relatively intact,and the soil erosion type was splash erosion.Also,

关 键 词：土壤结构 产流 产沙 壤中流 红壤坡耕地 

分 类 号：S157.1[农业科学—土壤学]