ISHS Acta Horticulturae 189: I International Symposium of the Research and Cultivation of Roses
EFFECT OF NH4/NO3 RATIO IN NUTRIENT SOLUTION ON GROWTH AND YIELD OF GREENHOUSE ROSES |
| Authors: | A. Feigin, C. Ginzburg, S. Gilead, A. Ackerman |
| Abstract:
The response of rose plants grown in a greenhouse to different NH4/NO3 ratios in nutrient solutions applied through trickle irrigation was studied. The plants were grown on a substrate of porous volcanic fragments (tuff) during the period of Oct. 1982 to July 1985, and were irrigated 4–5 times per day. Five complete nutrient solutions having NH3-N/(NH4+NO3)-N ratios-1 of 0, 0.125, 0.25, 0.375 and 0.5, with total N level of 10 mmol L-1, were tested. The average NH4-N/(NH4+NO3)-N ratios in the weekly collected leachates were approximately 0.02, 0.04, 0.07, 0.16 and 0.23, respectively, indicating that a considerable amount of the NH4 added was nitrified. The higher the NH4 ratio in the nutrient solution, the lower was the pH of the leachate. The presence of NH4-N in the nutrient solution increased flower yield and dry matter production. The greatest cumulative rose yield was obtained at the 0.25 ammonium/nitrate ratio treatment, having an average ratio of 0.07 in the leachate; the higher ammonium/nitrate ratio treatments resulted in lower yields during the summer, but not during the winter season. The chemical composition of the plant tissue was affected by the treatments and the levels of N and Fe were higher in the leaf tissue of plants that received NH4. | |
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