RESPONSE OF DATE PALM TREES TO DIFFERENT NITROGEN AND POTASSIUM APPLICATION RATES

The present study was carried out during the 2007 and 2008 growing seasons on ‘Zaghloul’ and ‘Hallway’ date palms grown in clay soil in a private orchard located at El-Tarh region, El-Beheira governorate, in order to study the effect of NK application on palm yield, leaf mineral content and fruit quality. Both fertilizers were applied at the rate of 0.0 (N₀ or K₀), 500 (N₁ or K₁) and 1000 (N₂ or K₂) g per palm. The data of both cultivars showed that the N and K fertilization resulted in a significant higher yield per palm than those of the control. The application of 500 and 1000 g K₂O significantly increased fruit weight and length. In addition, K fertilization increased fruit TSS whereas it decreased the tannins contents. Both fruit reducing and total sugars were significantly increased by potassium application. Potassium fertilization increased leaf N, K, Fe and Zn and decreased Ca, Mg and Mn contents, with the highest content by the higher rate. Nitrogen fertilization increased fruit tannins and decreased fruit TSS contents. ‘Zaghloul’ fruits had significantly higher fruit reducing and total sugars than ‘Hallway’ fruits. The percentage of leaf N, Ca and Mg content was increased with nitrogen application and with increasing the nitrogen rate. Moreover, leaf nitrogen content of ‘Zaghloul’ palms was significantly higher than that in ‘Hallway’.