Point Source Infiltration Soil Moisture Transport And Numerical Simulation

Point source infiltration irrigation technology has been a water-saving irrigation technology popularized in China and even the world in recent decades.Among them,drip irrigation technology in point source irrigation is widely used.In view of soil problems in northwest China,it is particularly important to study soil moisture movement under the condition of salinzed soil.The soil in this paper was selected from the salinized soil of junma farm in the north of yinchuan,and the one-dimensional water transport model of the soil in this area was established,and the one-dimensional water transport of the soil in this area was numerically simulated.The purpose was to study and analyze the law of soil water transport in this area,so that the results could guide the local soil improvement and planting.The main work is as follows:1.a lot of parameters will be involved in the establishment of a one-dimensional mathematical model of soil water transport,and the acquisition of these parameters needs to be tested and determined,including particle size analysis test,determination of water characteristic curve test and so on.Directly using particle size analyzer to determine particle size analysis test,the moisture characteristic curve through the film pressure meter to test soil samples of soil water characteristic test,and with Matalab software USES the VG model to simulate the moisture characteristic curve fitting,fitting out the results of the analysis and compare the model,obtained the VG model suitable for soil water characteristic curve fitting.2.The glass box soil point source infiltration test was carried out in the laboratory,and the accurate test plan was made according to the research purpose and actual situation.Carried out in accordance with the soil bulk density 1.5 g·cm-3 and the design of four flow test(2L/h?4L/h?6L/h?8L/h),according to the rigorous test,the test program in the process of sorting out record test all kinds of test data,the horizontal wetting front using direct observation method to record,vertical moisture migration using moisture sensor data are collected moisture content changes.3.Origin software was used to draw and analyze the wetting front formed in the X and Y directions on the horizontal surface in the process of point source infiltration.With the increase of flow rate,the wetting front distance becomes larger,but the migration law of 8L/h is the same as that of 6L/h.Origin software was used to plot the moisture content change data obtained at different depths under different drip irrigation flows,and analyzed that the infiltration depth and rate of water increased with the increase of flow rate,and the moisture content at the same depth increased with the increase of flow rate.4.resumes the one-dimensional moisture migration equation of soil moisture and moisture migration of point source infiltration under different flow conditions are numerically simulated,choose appropriate parameters and to rate the parameters in the process of simulation,simulation results obtained from numerical simulation and the test results the correlation is stronger,show that the parameters of model is suitable for the simulation of the moisture migration,and can be of certain guidance to the actual field planting.