Document Type : Research Paper
Authors
1
MSc student, Faculty of Agriculture, The University of Tabriz, Tabriz, Iran; Corresponding author, Associate Professor, Faculty of Agriculture, The University of Tabriz, Tabriz, Iran, respectivley
2
MSc student, Faculty of Agriculture, The University of Tabriz
3
Associate Professor, Faculty of Agriculture, The University of Tabriz, Tabriz, Iran, respectivley.
Abstract
Nitrogen is taken up by the higher plants in both nitrate and ammonium forms with different physiological impacts on the plant. An experiment was conducted to assess the effect of NH4:NO3 ratio in nutrient solution on the yield and quality of hydroponically grown strawberry (Fragaria×ananassa Duch) cvs 'Camarosa' and 'Selva'. Six replications per treatment were involved in a randomized complete block experiment. Four nutrient solutions differing in NH4:NO3 ratio (0:100, 25:75, 50:50 and 75:25) were applied. The nutrient solutions had significant effects on the strawberry plants so that the highest leaf area was observed in the plant grown with 25:75 ratio. Flower and fruit number were not affected by the solutions however, the weight of individual fruit increased with 25:75 ratio. Both high ratios of NH4 and NO3 in the solution reduced the yield. The yield was reduced by 33% and 80% in cvs Camarosa and Selva respectively, when the NH4 concentration increased from 25% to 75% in the solution. The highest and lowest photosynthesis (Pn) rate in both cultivars were observed at 25:75 and 75:25 ratios, respectively. Increased NH4 ratio in the solution significantly reduced postharvest life of the fruits in both cultivars. Both higher leaf area and Pn rate appeared to be the reason for the increased yield and plant growth in the 25:75 ratios of NH4:NO3. Therefore, a combination of two forms of N in an appropriate ratio (25NH4:75NO3) promote the strawberry plant growth, yield and quality.
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