Use of unequal salinity in the root zone to improve yield and quality in hydroponically grown tomato

The effect of an unequal distribution of salinity in the root zone on yield, quality and nutrient concentration in tomato plants (Lycopersicon esculentum Mill. var. DRK) was investigated in plants grown with split root system. The roots of each plant were divided into two portions and each portion was irrigated with nutrient solutions differing in Electrical Conductivity (EC) levels achieved by adding NaCl, KCI or all nutrients. When one portion of the roots received only water, the yield was only improved when the other portion was fed with high EC (6K/0 vs 6K/6K) but not at moderate EC (3K/0 vs 3k/3k). Furthermore, the yield of unequal EC (5/2.5) was better than that of equal EC (2.5/2.5; 515) nutrient feed. The reduced yield in the high EC treatment was due to the increased blossom end rot and reduced fruit size. High EC in both sides of the root system led to increase soluble solid and acidity in the fruits as well as reduced leaf area. When one portion of the root system was fed in water or low EC, the adverse effect of high EC was overcome. In treatments with unequal salt distribution, root volume was reduced in the portion given water. However, the main source of water uptake was from that portion of the root system in water. The concentration of Na in the leaves and fruit was reduced significantly where one portion of the root system was supplied with water. High or moderate EC achieved by adding K seems to have some advantages over Na. In general, unequal EC can be used for growing tomato plant in hydroponics to improve both yield and quality of fruits.