Abstract:The physical and chemical properties of magnetized brackish water changed significantly, so irrigation with such water is likely to influence the characteristics of soil water and salt movement. The constant magnetic water device with magnetization intensity of 300mT was used to magnetize brackish water with different salinities (0.14g/L，2g/L，3g/L，4g/L and 5g/L), and one-dimension vertical water infiltration experiment was conducted to reveal the effects of salinity of magnetized brackish water on water and salt movement in soil. Results showed that the soil infiltration rate and wetting front migration rate were decreased significantly with irrigation by magnetized brackish water, whereas the moisture content of the wetted zone was increased significantly. The salinity of brackish water had significant impact on the magnetic effect. When the salinity of brackish water was 3g/L, the relative reductions of cumulative infiltration and wetting front depth reached the maximum, and the relative increase of moisture content of wetted zone reached the maximum at the same infiltration time. Magnetized brackish water had significant impact on the parameters of Philip and Green-Ampt formulas. The soil sorptivity S, the saturated hydraulic conductivity Ks and the wetting front suction of magnetized brackish water were all less than those of the non-magnetized brackish water. There was significantly quadratic polynomial relationship among the relative sorptivity ΔS, the relative saturated hydraulic conductivity ΔKs and the salinity of brackish water. When the salinity of brackish water was 3g/L, the relative sorptivity ΔS and the relative saturated hydraulic conductivity ΔKs reached the peak value. Moreover, magnetized brackish water could enhance soil water retention capacity, thus the soil moisture content was increased significantly in the same soil depth. Magnetized brackish water could improve the desalination efficiency. In the soil depth of 0~20cm, the desalination efficiency of brackish water was greater than that of the non-magnetized brackish water, and when salinity of brackish water was 3g/L, the magnetic salinity intensity was the strongest, and the relative desalination effect turned out to be better.
