The research was conducted at the Homs Research Center during the 2022–2023 agricultural seasons, aiming to study the effect of foliar spraying with different concentrations of wood vinegar under varying levels of mineral fertilization, applied at a rate of three sprays during the season. The experiment was designed using a randomized complete block design and included nine treatments. (Foliar spraying with wood vinegar 3% and 6% and mineral fertilization 50% and 100% of the fertilizer recommendation combined treatments between them). The results showed significant superiority of the plants treated with 6% wood vinegar along with either the full or half of the recommended dose of NPK fertilizers (in terms of plant height and number of stems). The positive effect of wood vinegar on vegetative growth indicators contributed to improving productivity and quality parameters (number of small, medium, and large tubers; yield; starch content). The treatment involving 6% wood vinegar with the full recommended NPK dose resulted in (0.67, 3.67, 2.33 tubers/plant; 4.12 kg/m²; 9.00%, respectively), with no significant differences compared to the same concentration with half the NPK dose (0.83, 3.33, 2.33 tubers/plant; 4.03 kg/m²; 8.83%) over the untreated and unfertilized control.
Rawaa et al. (2025) studied this question.