Comparing the effect of various land use types on moisture dynamics in loamy soils with Hydrus-1D

Abstract The increasingly severe hydrological extremes observed over time are consequences of climate change in the Pannonian Basin. This study focuses on soil moisture (SM) patterns across three distinct land uses: pasture, Ploughland, and orchard situated in the Transdanubian Hills of southwestern Hungary. The study area is characterized by a subhumid continental climate. The study evaluates the effectiveness of the Hydrus-1D model in simulating SM in silt and silty loam soils. Gaining a deeper understanding of SM dynamics is crucial for improving soil management practices and mitigating the effects of drought across various land use types. From January 1, 2019, to February 28, 2023, matric potential, SM, and rainfall were measured across the three land sites. Monitoring stations were installed at shoulder and toe slope position, with sensors placed at 10 cm and 30 cm depths, respectively. Aridity indices over four years were calculated using the Thornthwaite equation. Our results revealed that SM dynamics were strongly influenced by land use. The studied sites displayed distinct water balances: the pasture site had the most positive water balance, while the orchard site exhibited the most negative balance, especially following the removal of cherry trees in 2022. The highest aridity index, 1.42, was observed at the orchard site in 2022. The pasture showed the least variability in SM, whereas the ploughland exhibited the lowest SM dynamics. Hydrus-1D sensitivity tests highlighted differences in error indices across the sites. These findings demonstrate the utility of Hydrus-1D in accurately simulating moisture distribution in the topsoil under various land use types.