Assessment of soil factors controlling ephemeral gully erosion on agricultural fields

Abstract

The soil factor is crucial in controlling and properly modeling the initiation and development of ephemeral gullies (EGs). Usually, EG initiation has been related to various soil properties (i.e. sealing, critical shear stress, moisture, texture, etc.); meanwhile, the total growth of each EG (erosion rate) has been linked with proper soil erodibility. But, despite the studies to determine the influence of soil erodibility on (ephemeral) gully erosion, a universal approach is still lacking. This is due to the complex relationship and interactions between soil properties and the erosive process. A feasible soil characterization of EG erosion prediction on a large scale should be based on simple, quick and inexpensive tests to perform. The objective of this study was to identify and assess the soil properties – easily and quickly to determine – which best reflect soil erodibility on EG erosion. Forty‐nine different physical–chemical soil properties that may participate in establishing soil erodibility were determined on agricultural soils affected by the formation of EGs in Spain and Italy. Experiments were conducted in the laboratory and in the field (in the vicinity of the erosion paths). Because of its importance in controlling EG erosion, five variables related to antecedent moisture prior to the event that generated the gullies and two properties related to landscape topography were obtained for each situation. The most relevant variables were detected using multivariate analysis. The results defined 13 key variables: water content before the initiation of EGs, organic matter content, cation exchange capacity, relative sealing index, two granulometric and organic matter indices, seal permeability, aggregates stability (three index), crust penetration resistance, shear strength and an erodibility index obtained from the Jet Test erosion apparatus. The latter is proposed as a useful technique to evaluate and predict soil loss caused by EG erosion. Copyright © 2018 John Wiley & Sons, Ltd.

Model prediction capacity of ephemeral gully evolution in conservation tillage systems

“…The BSTEM uses three default coefficients for silts depending on whether they are "resistant," "moderately erodible," or "erodible," encompassing two orders of magnitude variation depending on which value is selected. Our simulated soils would be classified as "moderately erodible" based on the τ c variation after the local refinement, with values in agreement with typical agricultural soils (Knapen et al, 2007;Knapen & Poesen, 2010;Ollobarren Del Barrio et al, 2018).…”

“…There is a need to better understand when EG are filled and re-form in subsequent years in the same place, as in the study by Wilson et al (2019). For this, it seems critical to understand the impact of soil characteristics on EG erosion (Ollobarren Del Barrio et al, 2018), specifically the uncertainty associated with critical shear stress and headcut erodibility (Wilson et al, 2020).…”

Gully erosion processes, disciplinary fragmentation, and technological innovation

“…Assuming that the gully material to be eroded is composed primarily of cohesive and non‐cohesive clastic sediment, the controlling parameters that could affect k d and τ c can include physical, geochemical, and biological properties as well as land management practices (Knapen et al, ; Grabowski et al, ), all of which can depend on time. For agricultural landscapes, functional relationships to predict the entrainment of soils typically include texture (sand, silt, and clay content), soil chemistry (concentrations of Na, K, Ca, and Fe and organic content), bulk density, and/or water content (Bryan, ; Römkens et al, ; Gilley et al, ; Liu et al, ; see reviews in Clark and Wynn, ; Ollobarren Del Barrio et al ., ; Su et al, ). Moreover, soil detachment may also depend upon the erosive forces applied (Rose, , ; Park et al, ; Nearing et al, ), and subsurface hydrologic conditions including piping (Tanaka, ; Huang and Laflen, ; Römkens et al, ; Bernatek‐Jakiel et al, ; Wilson et al, ).…”

Ephemeral gully erosion in concentrated flow channels induced by rainfall and upslope inflow on steep loessial slopes

“…The average EG width-depth ratio varied in the range of 1.13-1.83 in our study, which was similar to the results reported for the Loess Pla- was applied in our study compared with that of , which restricted concentrated flow incision within the EG (Bennett et al, 2000) and resulted in higher width-width ratios. However, torrid red soil with a higher clay content and black soil with higher clay and organic contents than loess soil may play a crucial role in restricting EG flow incision (Ollobarren et al, 2018) and contribute to much higher width-depth ratios.…”