Effects of Fertilization and Foliar Spray Treatment on the Ascorbic Acid Content of Tomato and Sweet Pepper

Abstract

The effects of foliar spray treatment and various fertilization on the ascorbic acid content of tomato and sweet pepper fruits were investigated.
In both cases crop growth was not greatly affected by foliar spray treatment, or by treatments with various compositions of nutrient solution. However, these treatments did affect the yield of both fruits. In tomato, the mean fruit weight increased with urea foliar spray treatment and with the 1/2P regime, but decreased with the 3/2N, 1/2K, and 1/2Ca regimes. In sweet pepper, the yield increased both with urea foliar spray treatment and with the 3/2P, 1/2Ca and 3/2Mg regimes of nutrient solution, and decreased with both the 1/2N and 3/2N regimes.
The ascorbic acid content of tomato fruit was not affected by the treatments with the exception of the 3/2K regime, which gave a remarkably high acid content. The influence of the treatment on the content of soluble solid and reducing sugars, on pH and on the titrable acidity in tomatoes was not clear. The ascorbic acid and sugars content of tomato fruit tended to increase with the ascending of the cluster position, there were positive correlattions (r=0.915) between the change of these two elements. Improvement of quality of tomatoes can be expected by incremental use of potassium fertilizer and by exposure the fruits to sunshine.
The ascorbic acid content of sweet pepper fruit increased with the 1/2P regime, but decreased with other regimes. The effect of treatment on the sugars contentin sweet pepper was not clear. The ascorbic acid content increased with the advancing of the harvesting period. The ascorbic acid of exposed sweet pepper fruits was higher than that of shaded fruits.