Variations in the disintegration rate of physical crusts induced by artificial rainfall in different alcohol concentrations

Disintegration is closely correlated with geological disasters and soil erosion. However, quantitative studies on the disintegration processes of physical crust controlling the soil surface erosion are limited. Therefore, we disintegration process in structural and sedimentary crusts induced by artificial rainfall on a typical cropland soil from the Loess Plateau, China. The physical crusts were immersed for 200 s at different alcohol concentrations applied for delaying disintegration process to obtain disintegration rate (DR). The content of organic matter and the sand percentage in the structural and sedimentary crusts decreased with increasing rainfall duration, while the bulk density, silt and clay percentages increased. The initial DR values ranged from ?0.01 to 1.82 in structural crusts and from ?0.01 to 1.47 in sedimentary crusts under different alcohol concentrations. DR decreased by 86.5%, 91.3%] in structural crusts and by 86.3%, 88.2%] in sedimentary crusts during the whole disintegration period. For both structural and sedimentary crust, the DR was the lowest when the rainfall lasted for 30 min, and finally stabilized at 0.19 and 0.18, respectively, at the disintegration time of 80 s. Notably, the 50% alcohol concentration slowed the disintegration process most efficiently. The structural crust had a lower erosion resistance than the sedimentary crust due to the lower DR. These results provide a theoretical method for evaluating disintegration process and timely information revealing the erosion resistance mechanism of physical crusts.