The migration of CO 2 in soil was simulated through use of soil column, especially the transformation of CO 2 between water and gas phases at wetting front was studied.

According to the determined result,the text analyze characteristics of soil water movement,such as the increased rate of the wetting front,the course of soil water content movement of the characteristic point,soil water distribution during irrigation and soil water redistribution after irrigation in wetting region.

The relationships of cumulated infiltration capacity and infiltration rate with the wetting front of infiltration were consistent with the Philips mathematical model.

In order to calculate the soil unsaturated conductivity of three different kinds of soil types on loess plateau under different temperature conditions,the quantitative experiments have studied the relations between characteristic curve and temperature factors, the relations between wetting front infiltrating speed,the water content of wetting front and average water content seperately.

In the course of the soil water redistributions after stopping irrigating,wetting front is passing to the outside constantly,and the soil water content of wetting layer increase in the beginning,and soil water content in the wetting region is generally reduced on later stage,and the region where the soil water is higher shifts down gradually,and soil water content is relatively stable to reach finally.

At the same time, the article described the latest experimental research achievement from the aspects of wetness shape, movement of soil water, flux of emitter, irrigation schedule, and so on.

The parameters of Gardner_Russo model for describing the soil retention curves are obtained based on the movement rules of horizontal one_dimensional soil water infiltration.

Through analyzing the types of the preferential flow in the study area, it indicates that the perceptible type of the preferential flow in young, mid-aged and over-mature is the approximate connected macropore flow and the one in the mature forest soil is unsaturated gravitational flow which is dominated by wetness front.

(1971)experimental condition. The simulated results agree to Warrick results. However,the results of FEM were more closed to Warrick results than FDM ones at the wet peak in the soil profile.

The transition of part of the free moisture into the bound state is taken into account by using a boundary condition on the wetting front.

The article discusses the one-dimensional problem of the leaching of a soil with piecewise-homogeneous initial salinization under conditions of a movable wetting front.

The minimum rainfall intensity and the minimum rainfall duration needed to infiltrate to the wetting front depth are calculated based on the Green-Ampt model.

As an example, we discuss more specifically the case of wetting of heterogeneous surfaces, where the change from a strong to a weak pinning regime could be induced in the wetting front by varying the surface tension of the liquid-air interface.

In this comment, we present a detailed theory of this process, supported by numerical calculations, confirming their conclusion that the wetting front moves with the square root of time.

In order to calculate the soil unsaturated conductivity of three different kinds of soil types on loess plateau under different temperature conditions,the quantitative experiments have studied the relations between characteristic curve and temperature factors, the relations between wetting front infiltrating speed,the water content of wetting front and average water content seperately.The results are described as follows:(1)Established three quantitative models in predicting unsaturated soil water conductivity...

In order to calculate the soil unsaturated conductivity of three different kinds of soil types on loess plateau under different temperature conditions,the quantitative experiments have studied the relations between characteristic curve and temperature factors, the relations between wetting front infiltrating speed,the water content of wetting front and average water content seperately.The results are described as follows:(1)Established three quantitative models in predicting unsaturated soil water conductivity of three soil types on loess plateau,K(θ)=ΔTaθb+KTre,and the models provided theoretical basis for finding out the dynamic change and appraising the availability of soil water.(2)Based on these models, the net increase of soil available water and soil unsaturated conductivity of different water content have been calculated with 1℃ increase of temperature and the clearer quantitative models of directly calculating temperature effect have been derived.

Drip irrigation was carried out under the conditions of various flow and irrigation quantity in two kinds of soil.By measuring the shift of soil moist peak and the relation among drip irrigation flow,irrigation quantity and maximum moist diameter in the vertical and horizontal direction were established ,which can be expressed as D(H )=(a+b q)Q c.The design parameters of drip irrigation,such as interval distance of dripper,flow and irrigation period were also determined in this paper.They were 90 cm,5...

Drip irrigation was carried out under the conditions of various flow and irrigation quantity in two kinds of soil.By measuring the shift of soil moist peak and the relation among drip irrigation flow,irrigation quantity and maximum moist diameter in the vertical and horizontal direction were established ,which can be expressed as D(H )=(a+b q)Q c.The design parameters of drip irrigation,such as interval distance of dripper,flow and irrigation period were also determined in this paper.They were 90 cm,5 L/h and 6-8 h respectively in dust clay and were 70 cm,3 L/h and 7-9 h in heavy dust loam in orchard irrigation.

Both Finite Difference Method (FDM)and Galerkin Finite Element Method(FEM)were used to solving the one-dimensional transient flow equation in unsaturated soil.Two FORTRAN77 programs were presented and used to simulate the soil moisture transfer in unsaturated soil under Warrick et al.(1971)experimental condition.The simulated results agree to Warrick results.However,the results of FEM were more closed to Warrick results than FDM ones at the wet peak in the soil profile.The results showed that both two numerical...

Both Finite Difference Method (FDM)and Galerkin Finite Element Method(FEM)were used to solving the one-dimensional transient flow equation in unsaturated soil.Two FORTRAN77 programs were presented and used to simulate the soil moisture transfer in unsaturated soil under Warrick et al.(1971)experimental condition.The simulated results agree to Warrick results.However,the results of FEM were more closed to Warrick results than FDM ones at the wet peak in the soil profile.The results showed that both two numerical method can be used to analyze and simulate soil moisture transfer in the soil.