Numerical Simulation Of Soil Water-salt Transport And Irrigation Schemes In Xingjiadu Yellow River Irrigation Area

In recent years,the decrease of water volume in the Yellow River,the contradiction between supply and demand of water resources and the problem of soil salinization restrict the development of Xingjiadu Yellow River irrigation area.Therefore,the research of water saving irrigation based on the law of water and salt migration is of great significance for maintaining the healthy and coordinated development of the agricultural production and ecological system in the study area.In this paper,Jiyang farm,which has serious soil salinization and no groundwater exploitation is taken as the the study airea.Through laboratory experiments and numerical simulation,the irrigation scheme and irrigation scheme are studied,and the optimized results are presented.The main contents are as follows:(1)The experiment of soil water and salt migration in study area.The typical plots were selected in Jiyang farm to carry out field and indoor experiments.The information of soil moisture,salt,groundwater level,groundwater quality and water quality were obtained under the 8 irrigation modes.At the same time,the measurement of crop yield could provide data support for the construction of numerical simulation model and optimal irrigation mode.(2)Study on numerical simulation model of soil water and salt migration.Hydrus-1D software is used to construct the numerical simulation model of soil water and salt migration.According to the experimental data and reference literature before irrigation,the boundary conditions and the relevant parameters such as soil flow migration and solute transport are determined.The test results show that the model has a high degree of fitting,which can provide reference for the management of the study area.(3)Research on irrigation mode.In view of the irrigation mode,the Hydrus-1D model was used to simulate the movement of soil water and salt in different irrigation modes,and the effects of soil water and salt change were analyzed and evaluated.The irrigation mode and irrigation quota are optimized according to the measured results and crop yield,at the same time,the suitable crop growth,high yield,high efficiency and water saving irrigation are used as the principles.The final irrigation mode is defined as irrigation quota of 52 m3/mu under the condition of flooding irrigation.(4)Research on irrigation schemes.Based on the optimized irrigation scheme and the rainfall forecast for different conditions,the Hydrus-1D model was used to simulate the soil water content and the change of the total salt.On the basis of the simulation results and analysis,with the aim of controlling salt,sustainable,combined with the actual situation of the years of irrigation,the irrigation mode of rinsing before sowing is proposed,which is more suitable for crop sowing.The final irrigation schemes are as follows:?No rainfall is considered:the rinsing quota before sowing is 52 m3/mu,the irrigation quota is 260 m3/mu during the growth period,the total irrigation quota is 312 m3/mu,and the actual irrigation can be combined with the rainfall situation.?The frequency of rainfall in different period of birth:75%(dry water),the rinsing quota before sowing is 52 m3/mu,the irrigation quota is 104 m3/mu during the growth period,the total irrigation quota is 156 m3/mu;25%(abundant water),the rinsing quota before sowing is 38 m3/mu,the irrigation quota is 104 m3/mu during the growth period,the total irrigation quota is 142 m3/mu.?Typical year(2018):the rinsing quota before sowing is 52 m3/mu,the irrigation quota is 156 m3/mu during the growth period,the total irrigation quota is 208 m3/mu.The irrigation methods for rinsing before sowing are all in the form of flooding irrigation,and the irrigation mode for growth period is 52 m3/mu under the flooding irrigation mode.