Study Of Water And Salt Movement In Saline-Alkali Soil With Different Irrigation Methods

It is an important ecological environment question in water shortage and soil salinization in sustainable agriculture development in Arid Northwest China. With rapidly development of the oasis irrigation farming in Arid Northwest China, it has caused more and more secondary solidifications land. Based on consult of a great number of literatures and datum both abroad and domestic, the paper has consulted the pounding infiltration and point source infiltration soil water and salt movement to search the relationship of irrigation modes and main irrigation technology elements and salt accumulation by the indoor soil column simulated simulation test, and to search the applicability of pounding irrigation and point source irrigation in salt soil. The results as follows:1. One dimensional pounding irrigation infiltration experiment indicates that the wetting water front increased with infiltration rate by the increasing infiltration heads, the relationship between wetting water front and infiltration time is power function in different water heads and soil bulks.2. The change of infiltration accumulation and time is described by power function in different soil bulks and water heads, it has less affect on soil bulks and water heads, but exponential b is increasing linear trend with the increasing water heads.3. The distribution of soil water content, electrical conductivity and concentration of Cl- in various water heads and soil bulks clearly show under water infiltration condition, there is a little change in water content, electrical conductivity and concentration of Cl- in the soil saturation area and the conduction, under each water head, soil water content, the electric conductivity and concentration Cl- are obvious along with the infiltration flood peak and the soil bulk specific gravity's influence difference.4. The desalination depth is increasing with the water head under the one soil bulk, but the increasing extent is little. The relationship between the proportion of desalination depth and soil water content is increasing with the increasing soil bulks; but redistribution is binging down, the bigger water heads the better.5. The surface water scope is bigger than irrigations and current capacity under the drip irrigation condition; it is the power relations with a drop current capacity when the surface water scope achieves the stable value. The drip irrigation moist body horizontal radius is bigger than the vertical radius, the horizontal radius is increasing with the irrigation and current capacity, the vertical radius is increasing with irrigation, but with the current capacity reduces; at the same time, the horizontal and the vertical radius are power relationship with the infiltration time, the soil water content is increasing with the increasing of drop current capacity and irrigation.6. A drop current capacity and irrigation the quantity also have the significant influence to the salinity distribution change characteristic. The soil salt content equivalent line distribution shape is similar to the soil moisture content equivalent line distributed shape; the desalinization horizontal distance is little increase with the soil bulk in a same drop current capacity and irrigation, but the vertical distance is decreasing; in the same current capacity and soil bulks, the irrigation is increasing, the horizontal and vertical distance are increasing. As a result, the increasing irrigation quantity is beneficial to form the desalinating areas of crop growth.