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Research Project: Managing Water and Sediment Movement in Agricultural Watersheds

Location: Watershed Physical Processes Research

Title: Effects of antecedent soil moisture on rill erodibility and critical shear stress

Author
item LI, M - LINYI UNIVERSITY
item LIU, Q - LINYI UNIVERSITY
item ZHANG, H - LINYI UNIVERSITY
item Wells, Robert - Rob
item WANG, LIZHI - LINYI UNIVERSITY
item GENG, JIBIAO - LINYI UNIVERSITY

Submitted to: Catena
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/2/2022
Publication Date: 5/16/2022
Citation: Li, M., Liu, Q.J., Zhang, H.Y., Wells, R.R., Wang, L., Geng, J. 2022. Effects of antecedent soil moisture on rill erodibility and critical shear stress. Catena. 216(A):106356. https://doi.org/10.1016/j.catena.2022.106356.
DOI: https://doi.org/10.1016/j.catena.2022.106356

Interpretive Summary: The current research focuses on the impact of antecedent soil moisture on the soil erosion process. Samples were prepared with six different soil moisture initial conditions, compacted into molds using the same procedure and force, then subjected to water scour under 3 different slopes and 3 different discharges; all tests were repeated in triplicate. Results show that soil moisture had an obvious effect on both erosion parameters (i.e. critical shear stress and soil erodibility) for both coarse- and fine-grained soils tested. Although the erosion response of coarse- and fine-grained soils were not similar, differences in critical shear stress and soil erodibility were not significant. The coarse-grained soil was modeled with a power function and the fine-grained soil was modeled with a polynomial function. Additional soil textures are required for further improvement and understanding.

Technical Abstract: Antecedent soil moisture exerts a complex, perhaps controversial effect on critical shear stress and soil erodibility. Critical shear stress and soil erodibility for a sandy loam and silty loam soil, representing a coarse- and fine-grained soil respectively, were measured using a hydraulic flume for six antecedent soil moisture conditions (i.e. 3, 6, 9, 12, 15, 18%). Samples were subjected to scour under nine different combinations of three slope gradients (i.e. 5, 10, 15°) and three flow discharges (8, 12, 16 L/min). The results show that antecedent soil moisture had an obvious effect on critical shear stress and soil erodibility for both coarse- and fine-grained soil. As soil moisture increased, soil erodibility for the fine-grained soil increased, reached a maximum, and then decreased, while for coarse-grained soil, soil erodibility decreased. Adversely, as soil moisture increased, critical shear stress decreased, reached a minimum, and then increased for the fine-grained soil, while for coarse-grained soil, critical shear stress decreased. However, the differences between critical shear stress and soil erodibility for the coarse- and fine-grained soil were not significant (i.e. p = 0.05). The relationship between soil erodibility and critical shear stress for the coarse-grained soil was modeled with a power function, and for the fine-grained soil the relationship was modeled with a polynomial function. Future work will include additional soil textures to study the influence of soil physical characteristics in combination with antecedent soil moisture on soil erosion.