Abstract
The influence of nitrogen (N) concentration in the fertilizer solution on growth and development of nutrient deficiency in 'Maehyang' strawberry (Fragaria ${\times}$ ananassa Duch.) was investigated. Tissue analysis for N concentrations based on dry weight of above ground plant tissue and those in petiole sap were also conducted to estimate nutritive condition of inorganic elements resulting in decreased crop growth. Plant growth was seriously restricted in N deficient plants. The new leaves were small and pale yellow green in color, whilst the older leaves became yellow with necrotic margin and died prematurely. The growth response of strawberry plants to the elevated nitrogen concentrations in fertilizer solution was quadratic with the heaviest dry weight of 5.5 g per plant at 120 days after transplanting. When the concentration of N at which plant growth retards by 10% is regarded as the critical concentration level, the N contents based on dry weight of above ground plant tissue should be in the range between 0.97 to 1.18%. The responses of fresh weight and NO$_{3}^{-}$N concentrations in petiole sap to the elevated nitrogen concentrations in fertilizer solution was quadratic and linear with the equations of y=10.42+2.275x-0.0955x$^{2}$ (R$^{2}$=0.4283$^{***}$) and y=34.73+6.638x (R$^{2}$=0.7615$^{***}$), respectively. From these equations, the optimal concentration range of NO$_{3}^{-}$N to prevent suppression of crop growth is between 80 to 145 mg.kg$^{-1}$ in petiole sap of 'Maehyang' strawberry.