Hydrosedimentology of paired watersheds with clayey soils under cattle grazing and no-tillage cropping: LISEM calibration and validation

Abstract

Hydrosedimentalogical models contribute to management of water resources, provided they are based on robust monitoring and calibration–validation strategies. The Limburg Soil Erosion Model (LISEM) properly represents runoff and sediment yield from watersheds with deep, clayey, weathered soils intensely occupied with grain production and dairy farming. Runoff and sediment yield in this agricultural environment have significant economic and off-site ecological importance, as the watersheds are connected to a large reservoir responsible for energy production and water supply. The objective of the study was to test whether LISEM is efficient in runoff and sediment yield modeling (calibration and validation) in paired watersheds with clayey weathered soils, under dairy cattle grazing and no-tillage grain production. The LISEM adequately represented runoff and erosion processes in the calibration phase (2018–2019), with Nash and Sutcliffe efficiency coefficient up to 0.94 and 0.92 for surface runoff, and 0.89 and 0.88 for sediment yield, respectively, for NW and SW watersheds. Some model parameters required significant adjustments, e.g., Ksat at 78.5% and 49.1%, initial soil moisture at 5.5% and 2.5%, soil cohesion at 24.1% and 4.6%, and aggregate stability at 21.4% and 4.6%, respectively for NW and SW watersheds. During the validation period (2020–2021), the model exhibited constraints in adequately representing the hydrosedimentological processes, with only a few rainfall events showing accurate results. Thus, for the utilization of a validated LISEM in future climate scenarios, the model still requires thorough scrutiny of the equations governing hydrology and erosion processes, along with continued monitoring and further model parameterization.