Objective The aim of the paper was to evaluate the effects of soil-water-redistribution medium (RM) shape on the migration characters of soil water and salt in takyric solonetz with the improving method of drip irrigation. And the result will provide scientific basis for the designing of the shape.
Method A comparative analysis of the soil water and salt transportation characters for the changing of RM shapes was done in laboratory by column experiment both in one- and two-dimensional infiltration.
Result For layered RM in one-dimensional vertical infiltration, the diffusion rate of vertical wetting front was larger for the smaller depth in 0-10 cm or bigger one in 10-15 cm. And the irrigation frequency increased as the depth of layered RM decreases, which facilitated the salt leaching. In two-dimensional infiltration with the semi-hemisphere RM, the diffusion rate of vertical wetting front was larger than the diffusion rate of horizontal wetting front. And both of the diffusion rates in vertical and horizontal direction were decreasing with the adding of RM diameter in steady infiltration stage. In addition, the salt leaching efficiency for per irrigation amount was decreasing while the value for per time was constant. At the steady infiltration stage, the diffusion rate both in vertical and horizontal direction kept decrease with the increasing of the diameter and changed little when the diameter was ≥ 20 cm.
Conclusion The RM shape affected the water infiltration and salt leaching process by the changing of irrigation frequency and per-time irrigation amount. Both the salt leaching efficiency of irrigation and the economy of the amelioration should be considered in the designing of RM shape in the application. For annual plants, the depth of the RM should be smaller once satisfied the growth of the plants. And the diameter of the semi-hemisphere RM should beyond 20 cm.
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