Application of HYDRUS-1D model to provide antecedent soil water contents for analysis of runoff and soil erosion from a slope on the Loess Plateau

• HYDRUS-1D could simulate reasonable antecedent soil water content (ASWC) values.
• The impact of ASWC on soil erosion was verified at the plot scale.
• Runoff and sediment yield increased with increased rainfall amounts and ASWC values.
• LAI and root depth are the only observed data required to run the HYDRUS-1D model.

AimsAntecedent soil water content (ASWC) is an important factor affecting soil water infiltration, runoff and soil erosion on slopes but it is difficult to measure or forecast accurately and is not often reported in soil erosion databases.MethodsRunoff plots (12 m × 5 m) were used to collect runoff and sediment during the rainy seasons between April 2010 and October 2013 on the Loess Plateau, China. The HYDRUS-1D model was calibrated and tested using the data collected from the plots. The relationships of ASWC with runoff and sediment yield were investigated using the model output values for ASWC.ResultsThe model performance was satisfactory, with a mean Nash–Sutcliffe model efficiency coefficient of 0.411 and a root mean square error of 0.031 during the four study years. Runoff was directly affected by rainfall amount and rain intensity. Furthermore, runoff typically increased with ASWC.ConclusionsHYDRUS-1D can provide temporal ASWC data that could be used for runoff prediction.