EFFECT OF SOME SOURCES AND RATES OF NITROGEN FERTILIZATION ON GROWTH AND LEAF MINERAL CONTENT OF YOUNG TREES OF “WONDERFUL”, POMEGRANATE

Abstract

This study was carried out during two successive seasons, (2013 and 2014) in a private orchard located at Giza governorate, Egypt. Study was conducted on one year old pomegranate trees “Wonderful” cv., planted at 3 X 4 m apart grown in sandy loam soil, under drip irrigation system by well water (2175-2425 ppm). Three nitrogen sources (S) were tested, Ammonium sulfate (20.5%), Ammonium nitrate (33.5%) and Urea (46%). Each source of nitrogen was applied at three rates (R):70, 140 and 210 g N /tree / year. Nitrogen fertilizer rate was divided through fertigation system with equal doses from mid-March till September during the two studied seasons. Ammonium sulfate at the rate of 70 g N /tree/year gave the highest values of stem diameter, shoot length, N , P , K , Fe and Zn leaf content , % dry matter of leaves and carbohydrate content in the wood and C:N ratio in the wood .whereas fertilizing with Ammonium sulfate at a rate of 140 g N/tree/year achieved the highest shoots number, leaf area, % dry matter of wood and leaf Ca content . Meanwhile, increasing Ammonium nitrate rate to 210 g N/tree/year ganed the best total chlorophyll in leaves, on the other hand, Urea at rate of 210 g N/tree/year gave the greatest leaf Mn content .So it could be recommended by fertilizing young wonderful pomegranate trees by Ammonium sulfate at a rate of 70 g N /tree/year devided info equal doses starting from mid-March till end September. Key words: Nitrogen - Fertilizers- Rates - Vegetative growth - Mineral Content - Young Pomegranate Trees -Wonderful.