Effect of super absorbent polymer on vertical infiltration characteristics of soil water

In order to determine the effects of super absorbent polymer on characteristics and dynamic changes of soil water infiltration, the dynamic changes of infiltration rates, cumulative infiltration, and wetting front of soil water under super absorbent polymer were analyzed through the lab experiments. The results showed that the influences of super absorbent polymer on infiltration rate were stable and consistent. Mixed (0-10 cm) and layered (5 cm) application of super absorbent polymer in upper soil layer would restrict soil water downward movement. After 30 minutes, the cumulative infiltration significantly decreased by 17.3%-6.6% and 5.5%-46.6% compared with the control. The restraining effect was increased with the increasing concentration of super absorbent polymer, and it was more obvious in layered application, especially in the concentration of 0.1%. Whereas, mixed (10-20 cm) and layered (10 cm and 15 cm) application of super absorbent polymer in lower soil layer had limited inhibitory effect, it reduced by 4.9%-11.9% compared with the control. While in layered application (10 cm and 15 cm) with the concentration of 0.1%, infiltration capacity of soil water would be enhanced, and the relevant cumulative infiltrations were about 1.1 times larger than the control. The water content in the soil layer with super absorbent polymer and the corresponding under soil layer would increase 1.1-1.9 times through layered application.