Effects of Wood-Derived Biochar on Soil Respiration of a European Beech Forest Under Current Climate and Simulated Climate Change

Biochar (BCH) amendments represent a valuable strategy for increasing forest carbon stock, but their effects on soil respiration of beech forests under climate change are largely unknown. We conducted a short-term mesocosm experiment investigating the impact of BCH applications (0%, 10%, 20%, and 50%, v/v) on respiration of a European beech forest soil in N-Italy. The experiment, carried out in Parma, was conducted under both ambient and modified climatic conditions, involving higher soil temperatures (c. +1 K) and reduced precipitation (−50%). The experiment was performed during autumn 2022 and repeated in spring 2023, periods representing late and early summer, respectively. Soil respiration significantly increased with BCH applications when compared to controls, irrespective of the percentage applied. The highest values were recorded in the 20% amendment, while values were significantly lower in BCH 50%, similar to those recorded in BCH 10%. Although soil respiration and soil temperature were positively correlated, no effect of simulated warming was observed. No effects of precipitation reduction were also found, despite respiration being significantly influenced by soil moisture. These results provide an initial insight into the potentially negligible impact of BCH applications on soil respiration in European beech forests under both current and future climate scenarios.