A simple experiment to characterize evaporation patterns in silty volcanic soil under different conditions

In geotechnical and agricultural problems, estimating the evolution of the hydrological state of the subsoil shallow layers is crucial for addressing stability. In large areas and over long periods, this requires theoretical predictions based on monitoring of weather conditions. In modelling the soil–atmosphere interaction, actual evapotranspiration is often estimated as a fraction of the potential evapotranspiration (computed from a reference potential evapotranspiration -RE- and a crop coefficient), basing on water availability in the topsoil. The paper presents a study aimed at deriving the trend in evaporative process under different crop conditions and the related drying-induced decays for a silty pyroclastic layer. The work is based on an experiment in which small containers, filled with the same silty pyroclastic soil, were prepared with three different crop conditions: bare, grass vegetated, and covered with burnt wood residues. Containers were exposed to dry weather conditions to characterize the different evolution of the evaporation processes, quantified by weighing the containers, and linked to RE by monitoring meteorological variables at the test site. The paper shows that the evolution of evaporation processes differs significantly for bare, vegetated and heterogeneous conditions, allowing quantification of crop coefficient and drying-induced decay for each case.