Search

• The soil erosion performances of frozen, nonfrozen and thawed soil were evaluated. • Four models were implemented to simulate the key parameters for thawed soil erosion. • The performance of SR and machine learning models were compared. • Influencing factors of straw returning on thawed soil were analyzed. Snow and ice‐melted water flow over thawed soil cause severe soil erosion. The application of straw mulch has long been considered as an effective measure to reduce soil erosion, but the effects of straw mulch and straw incorporation on thawed soil erosion remain uncertain. This study conducted detailed laboratory experiments to investigate the effects of straw mulch and straw incorporation on soil erosion and sediment transport of thawed soil. The median particle size (D 50) of transported sediment, flow velocity and sediment concentration for thawed soil were compared with that of unfrozen and frozen soil. Models based on Random Forest (RF), Support Vector Machine (SVM), Back Propagation Neural Network (BP) and stepwise regression (SR) were implemented to simulate the key parameters of thawed soil erosion, and the accuracy of the developed models was evaluated. The results showed that the sediment yield increased significantly in thawed soil compared with that in unfrozen soil. The maximum flow velocity over thawed soil decreased by 20.7 % compared with that over frozen soil. The D 50 of transported sediment decreased by 29.4 % after the soil suffered the effects of freeze–thaw, and the finer sizes were more likely to be entrained. The straw mulch effectively reduced the D 50 of transported sediment, flow velocity and sediment concentration. In addition, the RF model showed a better result to predict the sediment concentration, flow velocity and D 50 of transported sediment (NSE > 0.849, RRMSE < 0.493) than the BP, SVM and SR models. Comparing the performance of the RF model with the models reported in previous studies, the RF model showed the best performance. In general, the results of this study provide important information for soil erosion in thawed soil. [ABSTRACT FROM AUTHOR]