Soil moisture dynamics under various drought resilience measures in Mediterranean vineyards of the northern Apennines, Italy

Understanding soil moisture dynamics across different soils can help inform hydrological behavior and adaptation to changing climate conditions. The current study, therefore, investigated the relationship between soil moisture (SM) and main climatic, soil, and plant factors at different soil depths across various green manure management measures. The study is based on a three-year database consisting of 14 main climatic and soil properties at two (soil) depths of 0-30 and 30-90 cm. The vegetation variables are represented by four field demos in the Northern Apennines, Italy. On average, the SM in the topsoil (0-30 cm) ranged from 23 % to 29.8 % across treatments, while in the subsoil (30-90 cm) it ranged from 37.2 % to 42.9 %. Compared to the control, treatment U3 increased topsoil SM by approximately 17 %, whereas subsoil SM decreased by about 11 %. Moreover, soil temperature decreased by up to 0.8 °C under green manure treatments, indicating improved thermal regulation and moisture conservation. In all observed treatments, the SM at the 30-90 cm depth was higher than for the 0-30 cm horizon in all demo farms. The implemented green manuring treatments reduced the solo role of climatic factors and increased the contribution of soil temperature to SM. So, the managerial measures provided a relative increase in SM in the upper soil layer but did not significantly affect SM at the lower soil depth. Accordingly, an optimal level of plant residues is needed to maximize rainwater infiltration into the soil during green manuring. Complex interactions among hydrological processes and changes in rainfall, air temperature, soil temperature, evapotranspiration, dew point, wind velocity, and solar radiation were observed, depending on the interconnected soil management conditions. The study's results underscore the need to accurately predict the complex dynamics of shallow SM and the related hydrological processes in agricultural regions to cope with climate stresses.