Influence of Salinity and Nitrogen Levels on Growth, Yield and Nutrients Uptake of Tomato in Hydroponics Culture

This experiment was conducted to determine the effect of salinity and nitrogen on growth and yield of tomato and concentration and total uptake of some nutrients in different parts of plant in hydroponics culture. Nitrogen (N) was used at 0, 1.5 and 3% levels as NH4Cl and NH4H2PO4 and salinity consisted of 0, 30 and 60 mM as NaCl and CaCl2 (2:1 w/w). A completely randomized design experiment was carried out under greenhouse conditions. Results showed that fruit fresh weight increased with N application but salinity treatment decreased fruit yield. Maximum fresh weight was observed in treatment with 3% N and without any salinity application, whereas minimum fresh weight was obtained with 30 mM salinity and without any N application. Application of 30 and 60 mM salinity increased fruit phosphorous concentration significantly (P<0.05), but it did not affect shoot and fruit concentration. Nitrogen application increased fruit, shoot and root phosphorous concentration significantly. Root, shoot and fruit N uptake increased with N application (without salinity) whereas at high salinity level, increase in N uptake was lower than at low salinity level. Salinity increase without N decreased fruit phosphorous and manganese uptake, root copper, zinc and manganese concentration and shoot manganese uptake. Furthermore, results showed that at low salinity level, N application can alleviate the negative effects of salinity on growth and yield of plant.