Impact of expected climate change on soil water regime under different vegetation conditions

A mathematical model was applied for the Bükk Mountains (Hungary) to evaluate the effects of climate change on soil water balance elements and soil water regime. Model runs using SWAP model were performed for combinations of four distinctive soil types and three land use systems of arable land, grassland, and forest. The temporal variation of soil water regime under changing climatic conditions was examined considering no land cover change occurring in the future. The climate data consisted of the predictions of two regional climate models, the Swiss CLM and the Swedish RCA. The RCA results showed 45% to 50% and the CLM showed 5% to 14% higher future precipitation outlook compared to present conditions. Considering different land use types, the projected number of days with soil moisture deficit was the highest in forest ecosystems for both the upper 50 cm soil layer and the whole soil profile, which could be as high as 61% of days below optimal soil water content range. Our results showed increased water fluxes, especially in deep percolation in far future period and a strong influence of soil properties on the changes in the climate model results, indicating significant long-term effects of climate change on soil water regime.