Linking lysimeter and field sensor data to investigate water flow in a heterogeneous setting at the SUPREHILL vadose zone observatory

Direct measurements of water flow can provide valuable information that is not always attainable through sensors alone, however, combining methods is crucial for unlocking their full potential. Water flow monitoring is critical for the successful detection of pollutant fate in intensive agricultural production as a substantial amount of fertilizer and pesticide products are commonly used. Wick lysimeters are a common technique used for water flow measurements, where a quantity of drainage volume is measured over time. For mentioned purposes, passive wick lysimeters that maintain tension in soil by using an inert wicking material were employed in this study. This study presents a link between self-constructed passive wick lysimeters, volumetric water content sensors (TDR) and soil-water potential sensors used at the newly (2020) established SUPREHILL vadose zone observatory in Croatia, located on a hillslope vineyard. At the observatory, a network of lysimeters (x36) is installed throughout the hillslope and is accompanied by an extensive sensor network. The data from 2021 shows variability between lysimeters in regard to their position on the hillslope, as well as variability between its repetitions, suggesting the influence of soil heterogeneity at the observatory that possibly triggers preferential flow. Along with the data, a methodology for lysimeter installation and construction is presented.