Pyroligneous Acid Increases Productivity and Nutritional Quality of Greenhouse Tomato

Pyroligneous acid (PA) is a reddish-brown liquid obtained through the condensation of smoke formed during biochar production. PA contains bioactive compounds that can be utilized in agriculture to improve plant productivity and quality of edible parts. In this study, we investigated the biostimulatory effect of varying concentrations of PA (i.e., 0%, 0.25%, 0.5%, 1%, and 2% PA/ddH 2 O (v/v)) application on tomato ( Solanum lycopersicum ‘Scotia’) plant growth and fruit quality under greenhouse condition. Plants treated with 0.25% and 0.5% PA exhibited a significantly (p < 0.001) higher leaf transpiration rate and stomatal conductance. Total number of fruits was significantly (p < 0.005) increased by approximately, 65.6% and 34.4% following application of 0.5% and 0.25% PA, respectively compared to the control. The 0.5% PA significantly (p < 0.01) enhanced total weight of fruits by approximately, 25.5%; while the 0.25% PA increased the elemental composition of the fruits. However, the highest PA concentration of 2% significantly (p > 0.05) reduced plant growth and yield, but significantly (p < 0.001) enhanced tomato fruit juice Brix, electrical conductivity, total dissolved solids, and titratable acidity. Additionally, total phenolic and flavonoid contents were significantly (p < 0.001) increased by the 2% PA. But the highest carotenoid content was obtained with the 0.5% and 0.1% PA treatments. Additionally, PA treatment of the tomato plants resulted in a significantly (p < 0.001) high total ascorbate content, but reduced fruit peroxidase activity compared to the control. These indicate that PA can potentially be used as a biostimulant for a higher yield and nutritional quality of tomato