横垄坡面地表微地形多重分形特征及其对侵蚀产沙的影响  

Multifractal Characteristics of Surface Microtopography and Its Influence on Sediment Yield on Slope of Cross Ridge

作　　者：罗键[1] 郑子成[1] 李廷轩[1] 何淑勤[2] 

机构地区：[1]四川农业大学资源学院,成都611130 [2]四川农业大学林学院,成都611130

出　　处：《水土保持学报》2015年第4期66-72,共7页Journal of Soil and Water Conservation

基　　金：国家自然科学基金项目(41271307;40901138);四川省教育厅项目(15ZB0009);四川省学术和技术带头人培养资金资助项目(2012);四川农业大学学科建设双支计划团队项目(2014)

摘　　要：通过室内人工模拟降雨,分析递增和递减降雨条件下,紫色土横垄坡面地表微地形空间变化及其多重分形特征。结果表明,横垄坡面地表微地形变化满足多重分形算法要求,且在微尺度下递增降雨多重分形特征较为明显。递减降雨条件下,横垄坡面多重分形参数Δα、Δf随累积降雨量的增加分别呈现出波动下降和波动上升的变化趋势,地表起伏程度降低,微地貌趋于圆润;递增降雨条件下,f(α)max、Δα随降雨历时的增加不断升高,微地形变化较为剧烈,多重分形谱有明显的曲率变化段,空间异质性随降雨历时的增加不断加强,微地貌趋于尖锐。降雨雨型对横垄坡面产流量的影响高于对侵蚀产沙量的影响,递减降雨径流总量相较于递增降雨增加了16.04%,侵蚀总量则减少了3.57%,递增降雨更易促进土壤侵蚀的发生。对于地表径流量而言,回归方程决定系数达0.895 6,且具有统计意义上的显著关系,可利用降雨参数和地表微地形多重分形指标较好地预测坡面径流量。Based on artificial rainfall experiments,this study analyzed the spatial variation and multifractal characteristics of soil surface microtopography on slopes of cross ridge in purple soil region under increasing and decreasing rainfall series.The results showed that the change of soil surface microtopography on slopes of cross ridge satisfied the requirement of multifractal algorithm,and multifractal characteristics were more obvious at the micro-scale level under increasing rainfall series.Under decreasing rainfall series,multifractal parameters（ΔαandΔf）of soil surface on slopes of cross ridge were fluctuating,but respectively showed a declining and increasing trend with the increase of accumulative precipitation,and the degree of soil surface fluctuation reduced,with microrelief tending to be round.Under increasing rainfall series,f（α）maxandΔαincreased with the increase of rainfall duration,and surface microtopography changed significantly,with multifractal spectrum having obvious segment curvature change.Spatial heterogeneity increased with the increase of rainfall duration and the microrelief tended to be sharp.On slopes of cross ridge,the effect of rainfall pattern was more significant on runoff than on sediment yield.Under decreasing rainfall series,runoff volume increased by 16.04%,while sediment yield decreased by 3.57%,compared with those under increasing rainfall series.Therefore,soil erosion was easier to occur under increasing rainfall series.For the surface runoff,the determination coefficient of regression equation reached 0.8956,indicating that the relationships of surface runoff with rainfall parameters and multifractal indexes of surface microtopography were statistically significant.Therefore,surface runoff could be forecasted by using rainfall parameters and multifractal indexes of surface microtopography.

关 键 词：紫色土 横坡垄作 微地形 多重分形 径流量 产沙量 

分 类 号：P931[天文地球—自然地理学] S157.1[农业科学—土壤学]