Microtopographic Changes of Slopes under Different Planting Patterns and Their Responses to Rill Development in the Alpine Canyon Areas of Western Sichuan
Author:
Affiliation:
Fund Project:
摘要
|
图/表
|
访问统计
|
参考文献
|
相似文献
|
引证文献
|
资源附件
|
文章评论
摘要:
[目的] 为明晰高山峡谷区坡耕地不同种植模式对细沟形态变化特征的影响,选择适宜提升区域水土保持的种植模式。[方法] 以裸坡为对照,以花椒树+李树+鹤草、花椒树+樱桃树+五月艾、花椒树+豆角、李树+黄豆等主要种植模式的坡耕地为研究对象,采用原位径流小区冲刷试验与运动恢复结构(structure from motion,SfM)摄影测量相结合的方法,分析不同冲刷流量下(6、10、14 L/min)坡面细沟形态特征及其与微地形变化的关系。[结果] 1)相较于裸坡,不同种植模式侵蚀区面积达38.37%~78.43%;中大流量(10、14 L/min)条件下,不同种植模式下坡面粗糙度变化幅度均大于裸坡(-16.49%~11.56%);冲刷后15°~25°微坡度栅格占比提升0.70%~32.07%,60°~90°栅格占比降低1.40%~51.48%。2)不同种植模式显著改变坡面汇流形态,形成具有分形特征的“树枝状”径流网络,其中花椒+李树+鹤草模式在6、14 L/min流量下分形维数达1.465~1.476,具有较强的径流分散和泥沙调控能力。不同种植模式坡面细沟纵剖面形态均表现为“宽浅式”,宽深比较裸坡降低25.98%~72.79%。3)相较于微坡向和微坡度,不同种植模式坡面粗糙度与细沟纵剖面形态关系更为密切(p<0.01)。逐步回归分析表明,地面粗糙度是调控细沟发育的核心因子,通过优化地面粗糙度,可有效降低坡面细沟侵蚀风险。[结论] 研究结果可为高山峡谷区坡耕地水土保持措施合理配置与水土流失有效防控提供理论依据。
Abstract:
[Objective] This study aimed to clarify the impacts of various planting patterns on rill morphological characteristics in sloping farmland within alpine canyon areas,and to select optimal planting patterns for enhancing soil and water conservation in the region. [Methods] Using bare slopes as control,we investigated four main planting configurations as the research subjects, including Zanthoxylum+Plum+Candian fleabane, Zanthoxylum+Cherry+Artemisia indica,Zanthoxylum+Green bean,and Plum+Soybean. The morphological characteristics of hillslope rills and their relationships with microtopographic alterations under different scour discharge rates(6,10,and 14 L/min)were analyzed through in-situ runoff plot scour tests combined with the Structure-from-Motion(SfM)photogrammetry. [Results] 1)Compared to bare slopes,the erosion area for various planting patterns ranged from 38.37% to 78.43%. Under high flow conditions(10 and 14 L/min),the fluctuation in slope roughness for different planting patterns was more pronounced compared to bare slopes (-16.49% to 11.56%). After scour analysis revealed a 0.70% to 32.07% increase in 15° to 25° microtopographic units alongside a 1.40% to 51.48% reduction in 60° to 90° steep gradient segments. 2)Planting patterns altered the confluence patterns on slopes,resulting in a ″dendritic ″runoff network with fractal characteristics. At discharge rates of 6 and 14 L/min,the fractal dimension of the Zanthoxylum+Plum+Candian fleabane pattern ranged from 1.465 to 1.476,indicating superior flow redistribution capacity and effective regulation of hillslope sediment transport dynamics. The longitudinal profiles of rills under different planting patterns exhibited a ″wide and shallow ″morphology,with the width-to-depth ratio decreasing by 25.98% to 72.79% compared to bare slopes. 3)Compared to the micro-slope direction and micro-slope,the relationship between surface roughness and rill profile morphology was more closely associated(p<0.01). Stepwise regression analysis revealed that surface roughness was the key factor driving rill development,and optimizing surface roughness could significantly reduce the risk of rill erosion. [Conclusion] The findings of this research can offer a theoretical foundation for rational allocation of soil and water conservation measures,as well as for effective prevention and control of soil and water loss in sloping farmland located in alpine canyon regions.