Simulation Of Water-Salt Transportation In Soil And Optimization Design On Irrigation System

In the situation of the shortage of the water resource, developing and using new water resource become more and more important. As a new resource in the irrigation of agriculture, brackish water's research become the focus in the world, and it's used greatly. Because of the phenomena of soil salinization, it's important to research water and salt movement in soil and establish reasonable pattern in crop water-salt optimal control.This text has explained the soil water salt and transported the basic theories moved on the basis of the thing that the domestic and international brackish water's survey is utilized , have analysed the formulation of crop water salt irrigation system optimumly, proceed from sustainable development angle finally, point out subject matter in utilizing brackish water on agricultural irrigation and diligent direction in the future existing of the system management. Put forth effort to study the content of several respects of the following:1. Regarded SPAC system as the research object , established the water-salt balanced mathematics model in field, and set up the movement model of water-salt according to Darcy law and quality conservation principle, transporte two kinds of different model with mechanism analysis and sureness of the parameter.2. Analysed the method of solving the water-salt balanced mathematics model in field for growing crops; utilize implicit limited difference to solve move to soil water-salt movement model, realized the numerical simulation of water-salt movement; Then survey the numerical value and compare with measured date from experiment station: Movement model can describe the migration course of water-salt in soil sectional well, two model can also predict farmland variation tendency of water of salt and be used in crop irrigate design of system.3. Have studied the expression form of the water salt production function of crops, and apply it to optimum alternative irrigation system with salty and fresh water, adopt two grades method to set up the optimum irrigation models. Lead into soil water salt dynamic model as terms of controlling, finally compile the calculation procedure among model..4. With winter wheat's irrigation experiment of salty and fresh water in sheyang experiment station, calculate the optimum irrigation system in different design guaranteeing rate, offere the theoretical direction for the utilize of local brackish water resources and the management of salty-fresh water irrigation.Studies have shown: rational utilization of brackish water resources in irrigating the crops can solve the problem of the shortage fresh water resources well , prevent salinization of soil from occurring, and can improve the output of the crop , achieve the purpose in economizing on water, accusing of the salt, getting bumper crops, and have good economic and environmental benefits.