Development and applications of a portable erosion test device

Vegetation is an effective way to mitigate soil erosion; however, there is no portable device available to assess the erosion around a single plant. This study focused on developing a portable erosion device to assess erosion around a single plant in the field, which can also be used to assess cylindrical soil specimens. The device mainly consists of a speed-controlled agitator, a plat blade paddle, and a thin wall tube. The thin wall tube holds the water in which the paddle, connected to the agitator, will generate a vortex to mimic the flow around a plant. The applicability of the device was examined by a series of comparison tests and a shear stress analysis. For the comparison tests, the device was used to assess the erosion of the soil specimens and the soil specimens with a single plant root under different paddle revolution rates. The erosion was monitored for hours until the erosion rate became steady. The total amount of eroded soil was plotted as a function of time. Data indicated that the paddle revolution rate needed to exceed a threshold value to achieve consistent measurements. When the paddle revolution rate was less than the threshold value, the test showed poor repeatability due to the deviation in the surface texture among the soil specimens. The shear stress induced by the vortex was derived based on the paddle revolution rates, water viscosity and location of the paddle. It was found the erodibility of the tested soil, as a function of shear stress, was consistent with published data.