Experiment And Simulation On Soil Water And Salt Transport In Different Saline Soils Of Aral Reclamation Are

The salinization of arable land has become a major restriction and obstacle to the development and sustainable development of agriculture in Xinjiang factor.It is of great significance to study the soil infiltration process of saline-alkali cultivated land with different salinity degrees,and to identify its influencing factors and mechanisms,so as to improve and utilize saline-alkali cultivated land,and to promote the prevention and control of cultivated land salinization in Alar Irrigated Area.In this study,the soil of saline-alkali farmland with different salinity gradients in the downstream irrigation area of Tarim was used as the test object.The indoor soil column method was used to simulate the infiltration process of drip irrigation in the field,and the dynamic change characteristics of irrigation amount and dripper flow on water infiltration and the process of water and salt redistribution were analyzed impact.At the same time,HYDRUS-2D was used to simulate the distribution changes of water content and salt content in the soil under different drip irrigation conditions,and the lattice Boltzmann method was used to establish a seepage model to qualitatively analyze the effect of different porosity on the seepage of porous media.The main findings are as follows:(1)The volume of soil wet body increased with the increase of irrigation amount,and the volume of mild saline-alkali soil wet body was larger than that of severe saline-alkali soil wet body.With the increase of soil salinity,the water holding capacity of soil increases,and the infiltration capacity of saline-alkali soil decreases.Under the same irrigation amount,the horizontal wetting radius of mild saline-alkali soil decreased by 10.3%compared with that of heavy saline-alkali soil,and the vertical infiltration depth increased by 11.2%;the vertical infiltration rate of severe saline-alkali soil was 21.3%lower than that of mild saline-alkali soil.When the dripper flow rate was 2,4,and 8 L/h,the surface wetting radius of the wetting peak of the severe saline-alkali soil was 16.3%larger than that of the mild saline-alkali soil,and the vertical infiltration depth was 16.7%lower than that of the mild saline-alkali soil.The infiltration rate of mild saline-alkali soil under flow treatment was 11.9%higher than that of severe saline-alkali soil.The surface soil moisture content of severe saline-alkali soil is higher than that of mild saline-alkali soil.The closer the dripper is to the higher the desalination rate,the desalination effect of mild saline-alkali soil is more obvious.Increasing the flow rate of the dripper can increase the desalination area of the two soils.When the irrigation amount was 8L,12L,and 16L,the average moisture content of the soil layer above 10cm in mild saline-alkali soil was 12.7%,13.1%,and 13.7%,respectively,and the values of moisture content in severe saline-alkali soil were 13.2%,13.6%,and 14.3%.The power function was used to fit the migration distance of the wetting peak,and the coefficient of determination(R~2)of each fitting parameter was greater than 0.95.(2)The HYDRUS-2D soil moisture transport was simulated,and the results showed that the simulated values were in good agreement with the measured values,and R~2was greater than 0.9.The simulation accuracy in the horizontal direction is higher than that in the vertical direction.(3)The effects of porosity,growth nucleus distribution probability and directional growth probability on the construction of porous media were analyzed;a seepage model based on the lattice Boltzmann method was established.When n=0.6,the connectivity is better,and the seepage velocity is significantly larger than other treatments.The average velocity of seepage inside the porous medium increases with the increase of porosity.