Abstract:In order to investigate the differences in falling-head infiltration between fresh water and saline water, one-dimensional precipitation-head water infiltration column experiments were carried out for two soils, i.e., coastal saline-alkali soil and yellow-brown soil by using either fresh water or saline water with mineralization of 1.0g/L. The results showed that higher infiltration rates were obtained for saline water than for fresh water and the wetting front advance was faster for both soils. It indicated that saline water could enhance the infiltration capacity of the two soil types. This was especially so for the yellow-brown soil because it had better structure and was more readily affected by salt in saline water. The analysis of Philip infiltration modeling showed that the model was able to describe process of both saline and fresh water falling-head infiltrations in both soil types. However, the model predictions of measured yellow-brown soil data were poorer than those of salinealkali soil data. This was caused by soil sorptivity, which was a constant in the Philip model, and it could not describe the slight decrease in infiltration capacity, which occurred with increase of infiltration duration, as accurately for the yellow-brown soil as it could for the salinealkali soil. During the redistribution processes of water and salt, the salt leaching was similar under saline and fresh water infiltration in the upper levels of salinealkali soil columns because desalting was the main process occurred in those layers. However, salt accumulation was evidently greater under saline water infiltration than that under fresh water infiltration in layers closer to the wetting front. The salt content was increased in the upper layers while it was decreased in the deeper layers of yellow-brown soil under fresh water infiltration; but it was increased in all of layers under saline water infiltration; and the top and bottom layers both had the highest levels of saltiness, because the salt was retained specifically in the top soil layers due to the damage in the soil structure and the increase in water retention capacity, while it was leached from middle layers into lower layer to some extent.