Research progress of soil anti-scourability from 1962 to 2022

Soil anti-scourability is one of the most important parameters to evaluate the resistance to soil erosion in practice. This review aims to summarize the conception development of soil anti-scourability. A detailed overview was also provided for the relevant achievements in the soil anti-scourability research in China from 1962 to 2022. A systematical evaluation was performed on the pros and cons of characterization indicators and measurements in each period. An analysis was also made to clarify the influencing factors and mechanisms of soil anti-scourability. At the same time, the CiteSpace networks map was visualized to determine the cooperation relationship between authors and institutions, as well as the hot topics embodied by the keywords using the CNKI and Web of Science database. The results showed that the research on the soil anti-scourability sprouted in the 1970s, and then the heat continued to increase. The largest number of publications was reported in 2012-2017, accounting for 24.47% of the total number of publications. Furthermore, the number of publications accounted for 94.80% of the total number of publications over the past 30 years. Nevertheless, the number of publications accounted for 84.83% of the total since the 21st century. It infers that the research on soil anti-scourability rose in the 1990s, and the heat reached the highest in the early 21st century. The density of the author and institution network maps was 0.003, indicating the characteristics of 'large concentration and small dispersion. The density of the keyword network map was 0.006, among which the soil erosion, plant root, Loess Plateau, vegetation restoration, and shear strength were closely related to the keywords. The number of publications in the three stages of 1962-1982, 1983-2002, and 2003-2022 accounted for 0.89%, 19.71% and 79.40% of the total, respectively. Specifically, some keywords were drawn relatively high attention in the second stage, such as the Loess Plateau, soil erodibility, Robinia pseudoacacia forest, and litter. The hot topics with high attention in the third stage included soil and water conservation, hedgerow, soil erosion, and root system. The intensity of keyword emergence in the third stage was 1.04-2.86 times that in the second stage, indicating the generally improved research on the soil anti-scourability. More importantly, the research gaps and bottlenecks were also summarized in this field. It was difficult to compare the relevant research, due to the diversity characterization indicators and measurements on the soil anti-scourability. Consequently, it was suggested that the water requirement of 1 g of dried soil should be taken as the characterization index of soil anti-scourability. In the determination, the field water discharge scouring should be given priority, followed by the undisturbed soil scouring flume. There was a controversial influence mechanism of plant roots, soil physical and chemical properties, and slope on the soil anti-scourability. The mathematical model of soil anti-scourability was mainly built around the enhancement effect of plant roots in the loess area. It is still lacking in the interdisciplinary research on soil anti-scourability. The future study of soil anti-scourability should focus on the interaction between runoff erosion and soil anti-scourability at the slope and watershed scales. Modern technology can be used to reveal the resistance of soil structures to the runoff damage for better movement downward. The evaluation and prediction can also be made to clarify the influencing mechanism of the regional water and soil conservation, and ecological environment using the prevention and control of soil erosion, and the comprehensive treatment of water and soil loss. The finding can provide an important decision-making basis for the development of future water and soil conservation.