Akademik Veri Yönetim Sistemi
Turkish Journal of Agriculture and Forestry, cilt.20, sa.1, ss.35-40, 1996 (SCI-Expanded)
The effect of various NO-3/NH+4 / urea rates on the yield and quality of tomato, grown in peat+perlite under greenhouse conditions, was investigated. According to experimental results, when nutrient solution contained high percentage of NO-3, pH of the growing medium was increased. While NH+4 or urea caused pH to decrease. N, K and Fe concentrations of the plants were not affected by N sources and rates, but P and Mn contents of the plants were affected. Phosphorus concentration of the plants was found the lowest when the nutrient solution contained only NO-3. While it increased by the partial replacement of NO-3 by NH+4 or urea in the nutrient solution. Manganese concentration were found lower, when NO-3 found in the nutrient solution higher than 80%. However, Mn concentrations of the plants were increased when the rates of NO-3/NH+4/urea was 80/20/0, 80/10/10 or 70/20/10. The highest yield was obtained from The treatments containing NO-3/NH+4 / urea in the rates of 90/10/0 and 70/20/10. The hardness of the fruit was found to be higher in the treatments containing NO-3 plus NH+4 or NH+4 + urea than NO-3 alone. The pH and nitrate concentrations of the fruits were found lower in the treatments containing NO-3 and NH+4 or NH+4 + urea than the treatments containing N as only NO-3.