Effect of mineral nitrogen on shoot biomass and concentrations of some elements in alfalfa leaves under salinity conditions

Abstract:Effect of nitrogen on yield and accumulation of some ions in alfalfa were studied at saline condition. A factorial experiment was conducted based on completely randomized design with three replications in the University of Mohaghegh Ardabili, Ardabil, Iran, at 2010. Alfalfa seeds (Hamedani cultivar) inoculated with the Rhizobium bacteria and grown in 5 kg pots. Nitrogen fertilizer of 0, 30, 60 and 90 kg ha-1 was applied as urea at 4 to 6 leaf stage. After the establishment of seedlings, salinity was imposed at zero, 100 and 200 mM as NaCl. The amounts of sodium, potassium and calcium measured by flame photometer. Yield and Fe content also were measured. Results showed that salinity increased the amount of sodium, calcium and Fe ions significantly but it had no effect on potassium concentration. Sodium to potassium ratio and shoot biomass also decreased significantly by salinity. Although, nitrogen fertilizer had no significantly effect on the amount of absorbed ions but it increased alfalfa yield.