engleski

Estimation of hillslope water dynamics using extensive sensor-based equipment and laboratory methods

Soil critical (vadose) zone is one of the most complex terrestrial systems as it covers root zone, different soil layers, and compaction effects. Soil heterogeneities have an impact on soil water and solute dynamics, which is especially pronounced on sloping arable terrains (e.g., vineyards). Thus, we established the first Croatian critical zone observatory SUPREHILL to specify subsurface preferential flow and nonlinear agrochemical transport processes. By using extensive sensor-based equipment combined with laboratory and numerical methods, we will collect a wide range of data allowing us to accurately estimate heterogeneities on a local scale. Results collected with sensors showed higher volumetric water content values on the hilltop compared to the bottom part. According to results obtained using HYPROP, saturated water content is decreasing through the soil profile with depth. Results obtained using sensors showed lower volumetric water content in the upper horizons compared to the lower ones. The oscillations in water content were largest at the first depth (5 and 15 cm ) due to the faster impact of precipitation and evaporation on the surface horizon. Sensors showed higher water content on the hilltop on 5 and 90 cm depth, but lower on 45 cm compared to the bottom. Higher water content at the last depth at the top can be a result of a sharp increase of clay content (26 % at 60 – 90 cm, and 39 % at 90 – 110 cm) which could lead to increased water retention. On the other hand, according to HYPROP results, the hilltop has higher bulk density, lower porosity and hydraulic conductivity than the bottom part which can result in slower water flow and more steady water content. The differences can initiate preferential flow and nonlinear transport dynamics, which will be further investigated using soil columns, dye tracer experiments, CT-scanning, and numerical simulations.

preferential flow, soil heterogenity, hillslope, vineyard soil, water dynamics, vadose zone

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