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Black Soil Freeze-thaw Function Mechanism and Soil Erosion Simulation Study in the Spring Thaw Period

Author: LiuJia
Tutor: FanZuoMing
School: Shenyang Agricultural University
Course: Soil and Water Conservation and Desertification Combating
Keywords: Spring thaw period Freeze-thaw function Soil erosion simulation Black soil
CLC: S157
Type: Master's thesis
Year: 2011
Downloads: 10
Quote: 0
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Abstract


In the northeast of China, soil erosion has its unique erosion characteristics, the layer of black soil district frozen is deep, freezing time is long and widely distributed on slope surface, the impact to erosion gully erosion is very large, make the area agricultural productivity is reduced, sustainable development of agricultural production, land resource protection and the people’s production and life are received great harm. Serious freeze-thaw erosion gravity erosion with hydraulic erosion and composite up, to the industrial and agricultural production made a great impact. So far our country rarely have to carry out about freeze-thaw role in the spring thaw snowmelt and rainfall and not completely thawing period of soil erosion of quantitative research, making the relationship of this period to soil erosion in accurate prediction and evaluation.In this paper, mainly Investigation and analysis one of dryland farming soil in Northeast China—the nature of black soil, snow and spring thaw runoff, rainfall data, which have been combined research results to analyze the nature of black soil and its freeze-thaw conditions. Analysis of the inpact of freeze-thaw function of soil different moisture content on soil erodibility through freeze-thaw cycles experiment, analysis of the impact regulation of freeze-thaw effects on the black soil erodibility from the mechanism. Through the indoor simulation to the spring thaw period of black soil for the melting snow scour and indoor rainfall test, study the erosion of black for the spring thaw period.Draw the following conclusions:(1) Freeze-thaw functions taking impact on black soil erodibilityThrough change of freeze-thaw, physical and chemical propertiesof black that can change to corrosion, based on the mechanism of soil properties study found:freeze-thaw action to make soil bulk density decreases, porosity increases, reunion body water stability of the reduced, but its permeability, sticky gathered force and internal friction Angle changes are not obvious. In addition, different moisture content of the soil temperature, different freeze-thaw the physical and mechanical properties of have varying effects.(2) Snowmelt of thawing period taking impact on the slope soil erosionAfter the freeze-thaw cycle,slope erosion of black soil is higher then the trials without freeze-thaw; And both scour process in slope represents different erosion rules, freeze-thaw cycle after the slope erosion and the role with reduced sharply increased scour time after tend to fluctuate stable state.The analysis results of freeze-thaw erosion slope experiment showed that the freeze-thaw temperature and cycles, moisture content, flow rate, thaw depth have the varying degrees impact on the slope erosion. Flow rate which is the dominant factor, followed by the freeze-thaw temperature, moisture content, thaw depth and the number of freeze-thaw cycles. The slope after freeze-thaw cycle and the control slope existe significant differences in the slope development process through analysis 25 sets of experiments on the slope erosion process(3) Rainfall of thawing period taking impact on the slope soil erosionIn simulating rainfall in thawing period found that, soil moisture influence result to freeze and thaw is largest, rainfall intensity of second.than is soil thaw minimum depth; The erosion of the soil moisture content increases with the increase of soil moisture, increases with the increase of rainess, and increases in stabilizing after a time; Soil thaw depth can also affect the size of the slope erosion.

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