黄土坡面细沟侵蚀形态试验

Abstract

PDF HTML阅读 XML下载 导出引用 引用提醒 黄土坡面细沟侵蚀形态试验 DOI: 10.5846/stxb201309172298 作者: 作者单位: 西北农林科技大学 资源环境学院 黄土高原土壤侵蚀与旱地农业国家重点实验室,西北农林科技大学 资源环境学院;中国科学院 水利部 水土保持研究所,西北农林科技大学 资源环境学院 黄土高原土壤侵蚀与旱地农业国家重点实验室,西北农林科技大学 水土保持研究所,中国科学院 水利部 水土保持研究所 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金资助项目（41271299）；水利部公益性行业科研专项资助项目（201201083） An experimental study on rill morphology at loess hillslope Author: Affiliation: College of Resources and Environment,Northwest A F University,College of Resources and Environment,Northwest A F University,College of Resources and Environment,Northwest A F University,College of Resources and Environment,Northwest A F University,Graduate University Chinese Academy of Science 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:基于同一降雨强度下的室内连续模拟降雨试验，研究了典型坡度条件下黄土坡面细沟侵蚀形态，分析了细沟的空间分布特征、发育状况及距细沟沟头长度、细沟宽度和深度关系。结果表明：第1次降雨坡面以断续细沟为主，侵蚀方式主要为溯源侵蚀，细沟累积长度为39.3 m，坡面细沟总面积占试验土槽面积的14.2%；第2次降雨坡面以连续细沟为主，细沟沟壁崩塌增强，坡面的破碎程度增加，细沟累积长度增加32.1%，坡面细沟总面积增加115.6%。与第1次降雨相比，第2次降雨后细沟平均宽度、深度和坡面细沟侵蚀平均深度均增加，且在4-7 m坡段内增加幅度最大。单位斜坡长上细沟平均宽度和深度随斜坡长度的增加呈现先增加后减小的趋势，表明径流能量的消长对坡面细沟侵蚀发育过程及形态特征有明显影响。第1次降雨单条细沟长度均小于3 m，细沟宽度随距细沟沟头长度的增大而增大，第2次降雨则呈现先增大后减小的趋势，细沟深度随距细沟沟头长度的增加一直呈现先增大后减小的趋势，细沟宽度与深度的拟合关系最好，细沟深度随宽度的增加而增大，后趋于稳定。 Abstract:Rill erosion is known as the most important form of water erosion on agricultural land. Rill morphology plays a significant role in determining the runoff and soil loss from sloping farmland. However, few attempts have been done on the accurate description of rill throughout the study area for that eroding rill evolves morphologically in time and space. The objective of this study was to quantify the natural rill morphology under controlled laboratory conditions, aimed to provide more insight and detail information for later experiments. The soil used in this study was the loess soil with 28.3% sand, 58.1% silt, and 13.6% clay content from Ansai, Shaanxi province, China. It was collected from the top 20 cm in the A horizon of a well-drained site. The loess soil was packed in a soil box which is 10 m long, 3 m wide and 0.5 m deep, and performed to two sequent simulated rainfalls at an interval of 24 h. The slope was set as 15°. Each simulated rainfall lasted 65 minutes and the rainfall intensity was 60 mm/h. Rainfall intensity, rainfall uniformity and raindrop diameter were calibrated and reached the experimental requirements. In this study, the spatial distribution of rill erosion, rill development situation and relationships between the length away from rill head, rill width and depth were analyzed systematically. Results showed that discontinuous rills were widely distributed on the slope and headward erosion was the pre-dominant erosion manners in the first simulated rainfall. The accumulated length of all rills was 39.3 m and the total surface area reached up to 14.2% of the total soil box. However, the second simulated rainfall was mainly dominated by continuous rills, and the side-wall collapse of rills and fragmentation degrees of the slope strengthened. Meanwhile, the accumulated length increased by 32.1% and total surface area rose by 115.6%.Compared with the first simulated rainfall, average rill width, depth and rill erosion average depth all increased during the second run. And the increases occurred principally in the 4-7 m slope. The average rill width and depth of unit slope length increased firstly and decreased afterwards along with the increase of slope length. This indicated the growth and decline of runoff energy could affect the development processes and morphological characteristics of rill erosion. The length of each rill was less than 3 m and rill width increased with the length away from rill head for the first simulated rainfall. But the trend increased first and then decreased for the second simulated rainfall. Moreover, similar trends of rill depth developments were found for the two simulated rainfalls. The best regression relationship was found between rill width and depth. Rill depth increased with rill width at first, and then kept stable. 参考文献 相似文献 引证文献