INFLUENCE OF NITROGEN-SULFUR BALANCE ON TOMATO PRODUCTIVITY AND QUALITY TRAITS IN SOILLESS CULTIVATION

Abstract

Nitrogen (N) and sulfur (S) are crucial macronutrient elements for physiological and biochemical processes in tomato plants. However, synergistic effects of lowering N and increasing S application on tomato yield and quality have not been documented. The effect of four N/S balances: 50.00, 9.20, 4.66 and 2.92, prepared by varying the concentration of N and S, were evaluated in tomatoes grown in soilless medium (peat + perlite). The experiment was conducted in a completely randomized design with three replicates. The results of the study showed that the optimal N/S balance in the nutrient solution differed depending on the properties investigated. The N/S balance of 9.20 resulted in the highest overall fruit yield, average fruit weight, fruit size and diameter. Moreover, the N/S balances required in the nutrient solution for the highest lycopene content (7.69 mg 100 g−1 fresh weight) and vitamin C content (20.63 mg 100 g−1 fresh weight) in tomato fruits were 50.00 and 9.20, respectively. It was found that the N/S balance above or below 9.20 had negative effects on yield and yield components as well as on some biophysical quality characteristics of the fruit. However, the N/S balance had no influence on the number of fruits, the firmness and shape index and the pH value of the fruits. Therefore, lowering N and increasing S application to the balance of 9.20 would have great potential to enhance the synergistic effect on the productivity and quality of tomato cultivation.