Differences in the interception/throughfall balance and its influence on soil moisture regimes under forest, grassland and cropland canopies of a semi-arid continental flatland.

The seasonal variation of precipitation intensity in continental semi-arid flatlands determines the shifting influence of interception in the throughfall and soil moisture regimes under distinct vegetation covers including conifer, broadleaved, grassland and rainfed croplands (i.e., wheat). In a study case located at Sierra de Atapuerca, in the high plains of North Spain, where continental climate defines a very contrasting precipitation intensity between the cold and warm season, the study analyzes the seasonal difference between the low and high energy rain drops affecting throughfall and soil moisture recharge levels along the year. Results identify the distinct response of throughfall, and the subsequent soil moisture change to distinct rainfall events and its consequences for the sustainability of surface conditions afterwards. The study outcomes highlight the major role of vegetation type on modulating the throughfall and soil moisture evolution which influences the exposure of the surface to soil erosion. Snow remarkably distorts the throughfall/interception balance between seasons, representing a third type of alteration, particularly for soil moisture, concerning the vegetation cover. Secondary atmospheric variables such as relative humidity and radiation also seem influential in the soil moisture anomalies and soil surface developing under the different vegetation covers of this environment. The type of canopy cover additionally influences the interaction between different levels of the soil moisture profile which subsequently determines the resilience to drought of the vegetation cover. Consequently, the study contributes to understanding the reciprocal interaction between vegetation and hydrology in the definition of surface processes and land-surface sustainability.