土壤物理结皮的孔径的大小直接影响土壤水分下渗和气体交换。因此，本研究通过人工模拟降雨，选择塿土为研究对象，采用微型盘式入渗仪进行入渗试验，研究土壤物理结皮在不同降雨强度下的入渗情况以及孔径变化情况。结果表明：（1）在-0.5 cm压力水头下，结构结皮的吸渗率随着降雨历时先减小，在20 min时增大，沉积结皮的吸渗率随着降雨历时的延长一直减小；（2）两类结皮随着降雨过程的进行，大孔隙（孔径>0.5 mm）占比开始减小，中等孔隙（孔径介于0.3~0.5 mm）占比增加，结构结皮在20 min时小孔隙（孔径<0.3 mm）占比有所减小，沉积结皮中等孔隙的占比在10 min后保持不变；（3）两类结皮的平均孔径均随降雨历时的延长而减小。负压水头增大过程中，土壤结皮有效吸渗能力减小，当土壤结皮发育完全后，吸渗率趋于稳定。

Pore size in the soil physical crust directly affects soil water infiltration and gas exchange. However, few studies have investigated the changes in pore size within the soil physical crust during rainfall events. This study has utilized Lou soil as the research object and artificial rainfall simulations, with microdisk infiltration apparatus to study the infiltration of the soil physical crust under different rainfall intensities and the pore size changes. The results show that under the pressure head of -0.5 cm, the infiltration rate of the structural crust decreases with the rainfall duration and then increases after 20 min. As rainfall progresses, the proportion of large pores in the two types of crusts begins to decrease, and the proportion of medium pores increases. The proportion of small pores in the structural crust decreases at 20 min, and the proportion of medium pores in the sedimentary crust remains unchanged at 10 min. The average pore size for the two types of crusts was found to decrease with the extension of the rainfall duration. During the increase in the negative pressure head, the effective infiltration capacity of the soil crust decreased. When the soil crust developed completely, the infiltration rate tended to be stable.