Study On The Transport Characters And Parameters Of Water And Solute In Red Soil

Humanity's survival development cannot leave the water and soil resources. Practically, it has the extremely vital significance to strengthen the research of water and soil resources question research, to realize the water and soil resources sustainable use and promote economic society sustainable development. Describing the transport rules of soil water and solute scientifically and determining their transport characters and related parameters can provide data support for establishing prediction and forecast models of soil water and solute transport. And it is also important for soil water management and eco-environment protection.Using soil water dynamic and solute transport theory, combining with indoor simulation experiment, taking red soil in the south of China as the object, this paper discussed the effects of multi-factor on transport rules of soil water and non-absorbing Brsystematically and determined the related parameters of soil water and solute accordingly. The purpose of this study is to provide the basis for the movement of soil water in red soil region and the rational utilization of soil and water resources. The main conclusions in this paper are as follows:1) The antecedent moisture content of the soil accelerate water infiltration, but the increasing of soil density and the contents and size of sand stone block them. By fitting experiments data combining with Kostiakov model and Philip model, it was found that infiltration index K decrease continuously but a increase gradually with the increase of antecedent moisture content and soil density.Soil water diffusivity and soil volumetric moisture content can be expressed in power function approximately as D(θ)=aθb. Besides, the experiment results also show that using Green-Ampt model for one-dimensional horizontal infiltration is feasible., and the error between theoretical calculation and experiment measured less than 10.73%.2) Concentration gradient and water potential gradient effect the whole process of Br-horizontal transport. The concentration gradient plays a decisive role in the early stage, but the water potential gradient dominates in the later stage. The relationship between horizontal transport velocity and distance is in agreement with the power function relationship, expressing as v= aebx; Measured data shows that Dsh andθcoincide Dsh(θ)=aebθ.3) Soil texture and tracer concentration are important effect factors for the Br breakthrough of non-absorbing iron. By using CXTFIT model to fitting measured Br breakthrough curve(BTCs), the results show that the average porosity velocity(v) decrease, hydrodynamic dispersion coefficient Dsh and retardation factor R increase with the increase of soil density.