Sustainable Substrate Management in Soilless Tomato Cultivation: Combined Effects of Biochar and Wood Distillate on Plant Growth and Fruit Mechanical Properties

ABSTRACT Tomato production increasingly requires high‐yield plants and fruits with enhanced firmness and resistance to mechanical damage in order to reduce post‐harvest losses. Pre‐harvest treatments‐ may play a key role in modulating these quality attributes. This study investigated the effect of biochar, used as a partial replacement of agriperlite (2% and 4% v/v), and wood distillate (WD) on vegetative growth, yield, fruit quality, and mechanical properties of cherry tomato ( Solanum lycopersicum L., cv. Cikito) grown in a soilless system. Particular attention was given to mechanical parameters, including initial and mean firmness, apparent modulus of elasticity, deformation indices, absorbed energy, and elasticity. Biochar application, especially at 4% in combination with WD, significantly increased total yield and fruit number, while WD alone enhanced individual fruit weight and juice yield, particularly at the first harvest. Mechanical analyses showed that biochar improved fruit firmness and tissue stiffness, whereas WD promoted greater deformation and elasticity, indicating contrasting effects on post‐harvest behavior. Fruit color ‐ varied according to harvest stage, with significant biochar–WD interactions affecting L* and b* values. Overall, the use of biochar as a partial substitute for conventional soilless substrates together with WD application, represents a promising strategy to enhance plant performance and to modulate key mechanical and technological attributes of tomato fruits. However, further optimization of WD application timing and frequency is required to ensure agronomic effectiveness while maintaining economic and environmental sustainability.