Ammonium (NH4+): Nitrate (NO3-) ratio and its relation to the changes in solution pH, growth, mineral nutrition and yield of tomatoes grown in nutrient film technique

• Main Authors: Ismail, Mohd Razi, Othman, Abd Aziz
• Format: Article
• Language: English
• Published: Universiti Putra Malaysia Press 1995
• Online Access: http://psasir.upm.edu.my/id/eprint/3287/1/Ammonium_%28NH4%2B%29_Nitrate_%28N03.pdf; http://psasir.upm.edu.my/id/eprint/3287/; http://www.pertanika.upm.edu.my/Pertanika%20PAPERS/JTAS%20Vol.%2018%20(3)%20Dec.%201995/JTAS%20Vol.18%20(3)%201995%20(Pg%20149-157).pdf

The effects of NH4+ NO3- ratio on growth, water uptake, solution pH, mineral nutrition and yield of tomatoes were investigated using the nutrient film technique. There were six NH4+ NO3- ratios: 0:100 with and without pH control; 12.5:87.5, 25:75, 37.5:62.5 and 50:50 without pH control. There was an increase in pH of the nutrient solution with 0:100 and 12.5:87.5 ratios, but the pH decreased with 50:50 ratio. Higher NH4+ NO3- ratio reduced leaf and root growth. The reduction in leafand root growth could be attributed to reduction o fplant water uptake. Fruit fresh weight was reduced and the percentage of blossom-end rot increased with higher ratio of NH4+ NO3- in the solution. Increased ratio of NH4+ NO3- increased N content and decreased Ca content in all the plant tissues. P, K and Mg content decreased in leaf tissue with increasing NH4+ NO3- ratio.