Visualized experiment for observing infiltration process affected by preferential flow inside ring infiltrometer

Studying the effects of preferential flow on the infiltration process is of great importance to increase the accuracy of measurement. An experimental device was suggested to display water movement process in the soil during infiltration. The device consisted of a disassemble soil container, a halved infiltration ring and see-through container surface made of plexiglass plate. After infiltration ring was hammered into soil inside the container, the soil inside the halved ring was cut radially into two halves with a steel plate, part of soil outside the experimental part of the container was removed and a plexiglass plate was used to cover the soil inside infiltration ring for dynamic visualization infiltration experiment. Then the infiltration process in the soil profile within the ring can be observed. The structure of the device, working principle and its application methodologies were detailed. A series of infiltration experiments were conducted to demonstrate the working procedures of the device with silt loam taken from Beijing. The exemplary soil infiltrability processes were computed based on the water supplied into the ring during the experiments. The dynamic process of wetted area in the soil profile inside the ring indicated that preferential flow not only influenced the initial infiltration process but also affected the total infiltration process. The whole infiltration process was divided into three stages based on the infiltration characteristics produced by wetting soil, which were initial infiltration stage, transitional stage and steady infiltration stage, respectively. ©, 2015, Chinese Society of Agricultural Machinery. All right reserved.