保水剂对土壤水分垂直入渗特征的影响

为了探明保水剂对土壤水分入渗性能及变化过程的影响，该文通过室内积水入渗试验，比较分析了保水剂作用下土壤水分的入渗率、累积入渗量及湿润锋等的动态变化。结果表明：保水剂对入渗率的影响具有稳定性和一致性。上层混施（0～10 cm）和层施（5 cm）保水剂会限制土壤水分向下运移，30 min后累积入渗量分别比对照显著减少了17.3%～36.6%和5.5%～46.6%；而且随着保水剂用量增加，抑制效应增大。相比较而言，这种减缓入渗的程度在保水剂层施，且用量为0.1%时更为明显。下层（10～20 cm）混施和层施（10 cm和15 cm）保水剂对土壤水分入渗的抑制是有限的，约比对照降低了4.9%～11.9%；但当保水剂层施量为0.1%时，土壤水分入渗反而会随着入渗进程而增加，累积入渗量可达到对照的1.1倍。层施保水剂后，保水剂层及保水剂下层土壤含水率会普遍增加1.1～1.9倍。

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.