Physical simulation experiments of effects of macropores on soil water infiltration characteristics

The different size sands and macropores' mold were used to simulate the same macropores' depth and different effective surface macropores, and a novel soil column was designed to observe the 3D infiltration of macropore flow under the condition of ponding water. The results showed that there was high correlation between the time when the wetting front turned to flush and stable and the effective surface macropore. The cumulative infiltration was in line with the Kostiakov model while its parameters were associated with the effective surface macropores. Under certain conditions, macropores connectivity played the dominant role for the preferential infiltration in soil. The presence of macropores could lead to typical change of the center profile’s wet area. In the end, the study gave a quantitative concept for the center profile's wet area increment and its mathematical model with the effective surface macropores. The accuracy of the model verified by experiments can meet the requirments.