Abstract:
Date palm (Phoenix dactylifera L.cv Khedhri) seedlings were grown in perlite and irrigated with full strength nutrient solution and/or containing different concentrations (14, 28, 56, 112 or 224 ppm) of three nitrogen sources (nitrate, ammonium or urea). Treatment lasted for 9 months at constant temperature (30°C), 18 μE S–1 m–2 of 12 hr light and 60% RH.
Results of length and fresh weight of shoot and root systems as well as leaf area were recorded. In general and compared with minus nitrogen, concentration of 36 ppm of nitrate resulted in a highly significant increase in all growth parameters recorded. The use of ammonium resulted in a highly significant but gradual increase, with increase concentration except root length which was not affected. On the other hand, urea treatment did not result in any significant differences in those growth parameters. No clear effect of the nitrogen source on the nitrogen, calcium and chlorophyll was found.