Land cover influences microclimate and non-rainfall water inputs in temperate agricultural environment

• The type of land surface cover affects amounts of dew. • Non-rainfall water inputs (NRWI) include dew, fog, frost, rime, and soil water vapor absorption. • NRWI significantly contribute to the water balance across different land covers. • A refined method was developed to quantify and partition NRWI using weighing lysimeters. • In the temperate environment studied, most NRWI come from dew and sometimes fog. Non-rainfall water inputs (NRWI) from dew, fog, frost, rime and soil water vapour adsorption (WVA) are key components of the terrestrial water cycle, but their individual contribution to the water budget is unclear due to a lack of suitable methods for identification and quantification. Here, we present a refined method to quantify and partition NRWI using weighing lysimeters. The method’s novelty lies in the variables used to determine when dew and frost (leaf-wetness), fog and rime (air visibility) occur. We applied this methodology to grassland and arable land lysimeters and compared it to the established method that relies on relative humidity and estimated dew-point temperature to quantify and partition NRWI. Our results showed large differences between the refined and established method. The established method predicted larger amounts of dew (55 %) and WVA (2522 %), but no fog. NRWI mostly came from dew. Dew rates per event were generally higher on arable land, but the total amount of dew was larger on grassland due to higher frequency of dew formation. Dew amount differences could be attributed to land cover type, which promoted dew formation in the grassland while the arable ecosystem largely lost water through evapotranspiration (e.g. stomatal conductance, canopy-structure). We conclude that land cover type is a key control for microclimate (surface temperature, relative humidity), which significantly affects dew formation, while effects on fog or WVA are weaker. These effects are better determined by lysimeter assessment with a visibility and leaf-wetness device than by other existing NRWI identification systems.