EFFECT OF FOLIAR POTASSIUM APPLICATION ON TOMATO YIELD AND QUALITY

Potassium involving in physiological events within the plant affects the concentration of antioxidant compounds, which are effective on human health, in the fruit. Although the potassium content of the soil of the Mediterranean region is sufficient in general, calcareous alkaline soil conditions limit the plant's potassium intake and negatively affect fruit quality and coloration. In this study, effects of the foliar potassium applications (% 0, % 0.5, % 1, % 1.5, % 2) on the yield and quality of the tomato fruit in soil conditions that negatively affect plant potassium intake were investigated. The foliar potassium application was initiated after the flowering period and repeated 4 times with an interval of 15 days during the ripening period. N, K, Fe, Zn and Mn concentrations of the tomato plant were positively affected by the foliar potassium application. Fruit titratable acidity content increased depending on potassium concentration, while fruit juice pH decreased. Fruit vitamin C and lycopene contents increased with the potassium applications compared to the control. It was found that in soil conditions limiting the potassium intake, the foliar potassium application positively affected the quality of tomatoes and a dose of 1% potassium (K-2) might be recommended.