EFFECT OF SOME MAC. RO AND MICR0I NUTRIENTS ON MINERAL CONTENT, PRODUCTIVI1Y AND FRUIT QUALITY OF NAVEL ORANGE TREES

Abstract

Mahmoud Mohamed Mohamed Abd EI-Migeed. On The Effect of Some Macro and Micro Nutrients on Mineral dontent, Productivity and Fruit Quality of Navel Orange Trees. unbublished Doctor of I Philosophy dissertation, University of Ain Shams, Faculty of

Agriculture, Department of Horticulture (Pomolog ), 1996.

Two experiments were carried out on Javel orange trees during 1990, 1991 and 1992. The first on the ffect of potassium fertilization accompanied with spraying urea jor (urea +zinc + manganese + iron) on mineral content, yield nd fruit quality of Navel oranges. This experiment included two bets of treatments. Each set included five levels of potassium sulphJte namely (0, 150, 300, 450 and 600 g K20/tree/year). All trees dt the first set were

sprayed with 0.5 % urea and trees of the second set were sprayed with (urea + zinc + manganese + iron). N, P, k, Ca, Mg, and Fe content in leaves were not affected significJntly by different treatments while zinc and manganese contents\ were increased significantly due to spraying (urea +zinc + manganese + iron). Yield was significantly increased by different rates\ of potassium fertilization. The highest yield was obtained by 450 g K20/tree/year accompanied with spraying (0.5 % urea + 0.25 °o ZnS0 4 + 0.5 % MnS04 + 125 ppm Fe - metalosate) in May knd September. Physical and chemical properties of fruits were 1not affected by different treatments. The second experiment waon the effect of spraying mineral or chelated zinc and/or manga ese on mineral content, yield and fruit quality of Navel oranges. lrl this experiment zinc and/or manganese were sprayed at different doncentrations in the mineral or the chelated forms. Urea was added \o all treatments I to enhance absorption of zinc and manganese. The experiment included eighteen treatments and each treatment wJs sprayed twice in May and September in each season. The data cl ared that N, P