本文選題：HYDRUS　切入點：積水入滲　出處：《石河子大學》2015年碩士論文

【摘要】：滴灌具有明顯的節(jié)水、增產(chǎn)等特點。滴灌土壤水分和鹽分的分布規(guī)律是滴灌系統(tǒng)設計和灌溉制度制定的基礎,而一維土壤水鹽運移規(guī)律是研究土壤水鹽運移的基礎。通常研究土壤水鹽運移規(guī)律的方式是室外試驗,但室外試驗研究不但耗費時間、人力、財力,而且在試驗過程中容易受到自然和人為因素的影響,所以易產(chǎn)生較大的誤差。近幾年,計算機科學的發(fā)展迅速,國內(nèi)外許多專家開始利用非飽和水運動理論和溶質運移理論為基礎,構建數(shù)學模型對土壤水鹽運移規(guī)律進行模擬,此方法具有簡便、快捷、受干擾因素較少等優(yōu)點,其中HYDRUS軟件是目前模擬水分和溶質運移應用比較廣泛的計算機軟件。因此,本文利用HYDRUS軟件對粘壤土的土壤水分和鹽分的運移規(guī)律進行模擬研究。在以室內(nèi)試驗的基礎上,求得土壤水分和溶質運移的相關模型參數(shù),并驗證模型。通過模型模擬研究分析土壤容重、積水深度和初始含水率對一維積水入滲的土壤水鹽運移的影響,以及土壤容重和滴頭流量對點源滴灌土壤水鹽運移的影響。通過對不同試驗條件下土壤水鹽運移規(guī)律的分析,主要得出以下結果:(1)一維積水入滲的土壤濕潤鋒、入滲率和點源滴灌的土壤水平和垂直方向的濕潤鋒均與時間呈冪函數(shù)關系。(2)土壤容重、積水深度、初始含水率對一維積水入滲土壤水分的分布有顯著影響。土壤入滲率、濕潤鋒隨容重的增大而減小,土壤容重越大剖面平均含水率越小;土壤入滲率、濕潤鋒隨積水深度的增大而增大,土壤積水深度越大剖面平均含水率越大;初始含水率越大土壤入滲率越小,但濕潤鋒深度越大,土壤初始含水率越大剖面平均含水率越大。(3)土壤容重對一維積水入滲土壤鹽分的分布有顯著影響,在相同的初始條件和邊界條件下,容重為1.4g/cm3、1.45g/cm3、1.5g/cm3、1.55g/cm3,隨著容重的增大脫鹽系數(shù)減小、積鹽系數(shù)增大、表層脫鹽率和最大積鹽量減小,隨著容重最大積鹽率分別為210.64%、156.55%、110.04%、81.65%,最大積鹽位置為36cm、30cm、26cm、22cm。(4)積水深度對一維積水入滲土壤鹽分的分布影響較小,積水深度差值較大時影響顯著,在相同的初始條件,積水深度為1cm、4cm、7cm、10cm,隨著積水深度的增大脫鹽系數(shù)、積鹽系數(shù)、表層脫鹽率和最大積鹽量越大;最大積鹽率及其深度分別為156.55%、160.95%、165.09%、168.91%和30cm、31cm、32cm、33cm。(5)初始含水率對一維積水入滲土壤鹽分的分布影響有顯著影響,在相同的積水深度1cm和容重1.45g/cm3,初始含水率為0.05cm3/cm3、0.1cm3/cm3、0.15cm3/cm3、0.2cm3/cm3,隨著初始含水率增大脫鹽系數(shù)減、積鹽系數(shù)增大,表層脫鹽率減小、最大積鹽率減小;最大積鹽率及其深度分別為132.15%、100.00%、73.92%、52.91%和43cm、46cm、48cm、49cm。(6)土壤容重和滴頭流量對三維點源滴灌土壤水分和鹽分分布有顯著影響,容重越大垂直濕潤鋒越小,水平方向濕潤鋒越大;滴頭流量越大垂直方向濕潤鋒越小,水平方向越大。容重越大鹽分在土壤濕潤體內(nèi)分布越均為,脫鹽系數(shù)越小,積鹽系數(shù)越大,最大積鹽量越小;滴頭流量越大,鹽分在垂直方向脫鹽系數(shù)越小,積鹽系數(shù)越大,在水平方向脫鹽系數(shù)越大,積鹽系數(shù)越小。(7)HYDRUS模型能夠很好的反映滴灌條件下粘壤土的土壤水分和鹽分的運動規(guī)律。通過對模型參數(shù)的敏感性分析,其中經(jīng)驗參數(shù)n對模擬結果影響最大,剩余含水率θr對模擬結果影響最小,飽和含水率θs、α、Ks和αL對模擬結果均有一定影響。HYDRUS軟件反推土壤水力參數(shù)和溶質運移參數(shù)是一種簡單有效的方法,反推數(shù)據(jù)與實測數(shù)據(jù)可以較好的吻合。
[Abstract]:Drip irrigation has obvious water saving, yield and other characteristics. Distribution of soil water and salt under drip irrigation and irrigation system is the basis for making the design of drip irrigation system, and soil water and salt migration is based on one-dimensional soil water and salt transport. Usually the study of soil water and salt movement way is the outdoor test, but the experiment not only outdoor spend time, manpower, financial resources, and is affected by natural and human factors in the process of the experiment, so easy to produce large errors. In recent years, the rapid development of computer science, many domestic and foreign experts began using the unsaturated water movement and solute transport theory is based on the theory of constructing the mathematical model to simulate the law of soil water salt transport, the method is simple, fast, less interference factors etc., which is the calculation of the current HYDRUS software simulation of water and solute transport is widely used Machine software. Therefore, simulation study of the migration rule of using HYDRUS for the clay loam soil moisture and salinity. In laboratory tests on the basis of the model to obtain the parameters related to soil water and solute transport, and validate the model. Through the model simulation analysis on the influence of soil bulk density, soil water and salt transport in one-dimensional water infiltration of the water depth and the initial water content and soil bulk density and flow to drip irrigation soil water and salt transport. Through the analysis of soil water and salt migration under different experimental conditions, the main results are as follows: (1) the one-dimensional water into the soil wetting front infiltration, wetting front in soil level and the vertical infiltration rate and the point source drip irrigation was a power function relationship with time. (2) the soil bulk density, water depth, initial moisture content has a significant influence on the distribution of one-dimensional ponded water infiltration of soil moisture in soil. The infiltration rate, wetting front decreased with the increase of bulk density, the higher the soil bulk density profile average moisture content is small; the soil infiltration rate, wetting front increased with increasing water depth, soil water depth is large section average moisture content is higher; higher initial water content of soil infiltration rate is small, but the greater the depth of wetting front, the greater the initial soil moisture profile average water content is larger. (3) the soil bulk density has a significant influence on the distribution of one-dimensional ponded water infiltration of soil salinity, under the same initial conditions and boundary conditions, the density was 1.4g/cm3,1.45g/cm3,1.5g/cm3,1.55g/ cm3, with a decrease of increase of desalinization coefficient bulk density, salt accumulation coefficient the surface, desalination rate and maximum salt accumulation amount is reduced, with the maximum density of salt accumulation rate were 210.64%, 156.55%, 110.04%, 81.65%, the largest salt accumulation position is 36cm, 30cm, 26cm, 22cm. (4) water depth of one-dimensional water infiltration of soil salinity Little impact on the distribution of water depth difference effect significantly, in the same initial conditions, the water depth is 1cm, 4cm, 7cm, 10cm, with the increase of the depth of the water desalting coefficient, salt accumulation coefficient, desalination rate and maximum surface salt accumulation is increased; the maximum rate of salt accumulation and its depth is 156.55%, 160.95% respectively. 165.09%, 168.91%, and 30cm, 31cm, 32cm, 33cm. (5) initial water content has a significant influence on the distribution of soil salinity in the one-dimensional water infiltration effect, in the same water depth and density of 1cm 1.45g/cm3, the initial moisture content is 0.05cm3/cm3,0.1cm3/ cm3,0.15cm3/cm3,0.2cm3/cm3, with the initial moisture content. The desalinization coefficient reduction, salt accumulation coefficient, surface the desalting rate decreased, the maximum rate of salt accumulation decreased; the maximum depth and salt accumulation rate were 132.15%, 100%, 73.92%, 52.91% and 43cm, 46cm, 48CM, 49cm. (6) of soil bulk density and flow of 3D point source drip irrigation Have a significant impact and salt distribution, the greater the density of vertical wetting front is smaller, the horizontal wetting front is larger; the emitter flow the greater the vertical wetting front is smaller, the horizontal direction is greater. The greater the density of salt distribution in the soil body are more humid, desalination salt accumulation coefficient is smaller, the greater the number of lines the largest, salt accumulation amount is smaller; the dripper discharge more salt in the vertical direction of the desalinization coefficient smaller, salt accumulation coefficient is larger in the horizontal direction, the desalting coefficient increases, salt accumulation coefficient is small. (7) the HYDRUS model to the motion law of soil water and salt clay loam is a good reflection of drip irrigation next. Through sensitivity analysis of model parameters, the parameter n is the greatest impact on the simulation results, residual moisture content of 9 R with minimal impact on the simulation results, the saturated moisture content of s alpha, theta, and alpha Ks L were on the simulated results will influence the soil hydraulic parameters estimation software.HYDRUS and solute transport The moving parameter is a simple and effective method. The backstepping data and the measured data can be in good agreement.

【學位授予單位】：石河子大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：S152.7

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