Abstract:
Abstract: The fresh water resource shortage severely increased in some regions, and the reasonable application of brackish water could alleviate the contradiction between water supply and demand. Hence, effective measures should be taken to regulate the condition of soil water and salt under brackish water irrigation. De-electronic water treatment technology is a new physical water treatment technology, which has received increasing attention in recent years. In order to improve the efficiency of brackish water utilization and alleviate the shortage of agricultural water supply, the de-electronic processor device was used to treat the brackish water with different salinity (0.14, 2, 3, 4 and 5 g/L), and the effect of de-electronic brackish salinity on water and salt movement in soil was revealed by a vertical infiltration experiment. The results showed that the soil infiltration rate and wetting front migration rate were significantly improved by the infiltration of de-electronic brackish water, and it would be varied under different salinity of brackish water. When the salinity of de-electronic brackish water was 3 g/L, the cumulative infiltration amount and wetting front depth reached the maximum at the end of infiltration. Compared with untreated brackish water, the de-electronic brackish water had a maximum relative cumulative infiltration amount and wetting front depth under brackish water condition of 4 g/L salinity. When the infiltration time was 200 min, the cumulative infiltration amount and wetting front depth were relatively increased by 20.5% and 23.1%, respectively, and the infiltration time was reduced by 34.4% after infiltration. The parameters of Philip and Green-Ampt formulas were significantly influenced by de-electronic brackish water. The soil treated by de-electronic brackish water had a greater value of soil sorptivity, saturated hydraulic conductivity and wetting front suction than untreated brackish water. The relationship between sorptivity and salinity of de-electronic brackish water can be described by a quadratic polynomial equation. And the effect of brackish water salinity on saturated hydraulic conductivity can be described by a quadratic polynomial equation as well. When the salinity was 3 g/L, sorptivity and saturated hydraulic conductivity reached the maximum under both conditions of de-electronic brackish water and untreated brackish water. Moreover, de-electronic brackish water could enhance soil water retention capacity and salt leaching effect. For the same soil depth, the soil moisture content increased significantly, especially in the depth range of 20-25 cm. The soil water content within the depth of 20-25 cm relatively increased by 29.5% at the salinity of 4 g/L. Saline content and Na+ content at the depth of 27 cm were obviously higher than that of untreated brackish water after infiltration. The salt and Na+ relative leaching rates were 16.5% and 19.9% respectively at 4 g/L brackish water. And it had a great desalination effect owing to the highest salt and Na+ relative leaching rates. The results of this study prove that de-electronic brackish water can improve soil water movement and enhance salt leaching effect. Meanwhile, the utilization rate of brackish water can be significantly increased. This study can provide a theoretical support for the application of de-electronic brackish water in agriculture irrigation.