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黄土高原模拟降雨条件下坡地植被配置模式与水土流失关系研究
Alternative TitleStudy on the relationship between vegetation pattern and soil water loss on slopes under artificial rainfall conditions in the Loess Plateau
冯欣然
Subtype硕士
Thesis Advisor卫伟
2019-12
Degree Grantor中国科学院生态环境研究中心
Place of Conferral北京
Degree Name工程硕士
Degree Discipline环境工程
Keyword黄土高原,水土流失,模拟降雨,植被配置 loess Plateau,soil And Water Loss,vegetation Pattern,artificial Precipitation
Abstract

      黄土高原地处干旱半干旱区,水土流失严重。该区降雨集中在7-9 月份,多
以大到暴雨形式出现,加之土壤结构松散,抗蚀能力差,这些自然因素导致该区
水土流失严重。历史上人类不合理开发利用导致该区植被覆盖情况差,人为扰动
强烈,进一步加剧了水土流失。20 世纪90 年代以来,中国政府在该区实施了退
耕还林还草等一系列大规模生态修复工作,到目前该地区的植被覆盖率有显著增
长。本研究实验样地位于黄土高原地区的甘肃省定西市,降水以大暴雨形式集中
在夏季,容易发生降雨事件引起的水土流失。本实验希望通过人工模拟降雨的方
式,研究坡地尺度上几种不同植被坡位配置对产流产沙的影响,目的在于在各种
资金、人力、人工植被物种条件有限的情况下,找到防止坡面水土流失最有力的
植被配置,为当地人工种植植被、防治水土流失提供最优策略和理论指导。
      实验分为六个同坡向、有相同的坡面面积(7.5m×1.5m)、坡度25°的小
区,按照每个同物种斑块2.5m×1.5m 的面积栽种于各小区的上、中、下坡位,
使每个小区都有三种植被的不同组合,以此代表三种不同的植被类型(乔木、灌
木、草本植物)。按照从1 号到6 号小区、坡位从上到下的顺序依次为:1.乔-
灌-草,2.乔-草-灌,3.灌-乔-草,4.灌-草-乔,5.草-灌-乔6.草-乔-灌。总共记录54次降水事件。
本研究初步取得以下进展:
      (1)揭示植被配置模式和雨强对坡面径流泥沙特征影响特点
      模拟降雨条件下植被配置模式为灌木-草本-乔木的小区在中小雨强和短历
时降雨(<80min)有最低产流产沙量,而灌木-乔木-草本的坡面小区在大雨强或
长历时降雨(>90min)时有最低产流产沙速率;坡面上坡位种植乔木的小区相对产流产沙速率最大。在实际配置时可以种植盖度低的灌木,而中下坡位可以种植较大生物量的植被,这样可以获得最大的减流减沙效益。
      (2)阐明各自然环境因素对坡面产流产沙的统计学关系
      秩相关分析和冗余分析等统计学方法研究表明,径流量和产沙量首先对降雨
强度有非常显著的相关性,坡位植被参数对所有雨强下的所有产流产沙参数都存在显著(p<0.05)影响,这反映出本实验随雨强出现不同产流形式。环境因素能
够解释90%以上产流产沙特征,不同雨强下,产流产沙解释度最大的影响因素并
不一致。结果提示在植被总量有限时,应该优先配置在中下坡位,避免将其集中
在上坡位。统计分析结果与实验研究结果一致。
      (3)对Philip 公式予以改进,构建了一种植被影响下坡面产流产沙数值模
拟方法
      基于Philip 公式及其改进形式,可以对实验中降雨径流、产沙过程进行有效的预测和分析。通过修正原Philip 模型截留和填洼过程,本研究构建的改进的基
于Philip 模型的植被配置模式和雨强影响下的产流预测方法,该方法模拟效率较
高,有一定推广价值。
       本研究成果可以用于指导人工种植植被时将低生物量的植被种于坡顶/上坡
位,将大生物量的乔木等种植于中下坡位,这样有利于防治坡地水土流失。

Other Abstract

      The loess plateau, belonging to inner Asia, is one of the areas suffering the most serious soil and water loss in the world. On the results of worldwide researches we could find the climate, soil, vegetation factors as long as history and human activities have functioned together to induce soil erosion and water loss in the loess plateau.However, China government regarded this problem and has been pushing politics
such as afforestation, Soil and Water Conservation Projects from the 90th of last century, which have made significant growth of vegetation coverage and reduction of soil and water loss in this area.
      As for this research, we site in Anjiapo watershed, Dingxi City, Gansu Province,which has a typical loess plateau landscape and semiarid continental climate. Around this site there are abundant of loess slopes, ridges, hills and valleys, and precipitations always happen during the summer as heavy rains. That makes soil and water easy to lose. We hope to research the impacts of precipitation on different vegetation patterns
and their runoff and soil erosion on slope scale with artificial precipitation facilities, in order to find out the best arrangement of different vegetation patches on the loess slopes, and provide planting and soil-water retaining solution for authorities with limited money, human resources and plant species available.
      The experimental site is divided into six plots with the same slope direction. the same slope area of 7.5m *1.5m, and the slope of 25°. Each district is surrounded by concrete walls to prevent water permeability. Artificially cultivated vegetation species are Platycladus orientalis, Caragana korshinskii and Agropyron cristatum. The vegetation age is about 6-7 years. They are planted on the upper, middle and lower
slopes of each plot according to the area of 2.5m *1.5m per patch of the same species, so that each plot has three different combinations of vegetation, representing three different vegetation types (arbors, shrubs, herbs). According to the order of plot 1 to 6 and slope position from top to bottom: 1. arbor-shrub-herb, 2.arbor-herb-shrub, 3.shrub-arbor-herb, 4.shrub-herb-arbor, 5.herb-shrub-arbor, 6.herb-arbor-shrub. Artificial rainfall using Norton artificial precipitation equipment in the United States can better simulate the falling form and momentum of natural
rainfall, and can set up a variety of rainfall intensity. In this experiment, there are three kinds of rainfall intensity: small, medium and large. The ratio of rainfall intensity is 1:2:4.
      Fifty-four sets of runoff and sediment yield data were obtained, which belonged to six plots with three rainfall intensities, integrated environmental factors, vegetation factors and time parameters.
      The results showed that there was a significant negative correlation between runoff and biomass at the uphill site, and there was a relatively minimum runoff and sediment yield/rate in plots 3 and 4. Under the same total biomass allocation, the shrub with the lowest biomass had the best effect of reducing runoff and sediment at the uphill site.
      The Philips formula and its improved form can effectively predict and analyze the rainfall runoff and sediment yield process in the experiment. Through the modification of the original Philips model in the process of interception and filling, the improved vegetation pattern based on Philips model and the prediction method of runoff yield under the influence of rain intensity are constructed in this study. The improved method has high simulation efficiency, and it has certain promotion value.
      This conclusion can be used to guide the planting of artificial vegetation by planting low biomass species on the top/upper slope and planting large biomass trees on the middle and lower slope, which is conducive to the prevention and control of soil erosion on slope land.

Pages82
Language中文
Document Type学位论文
Identifierhttp://ir.rcees.ac.cn/handle/311016/42196
Collection城市与区域生态国家重点实验室
Recommended Citation
GB/T 7714
冯欣然. 黄土高原模拟降雨条件下坡地植被配置模式与水土流失关系研究[D]. 北京. 中国科学院生态环境研究中心,2019.
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