EFFECT OF SOME MACRO NUTRIENTS SPRAYS ON MINERAL STATUS, YIELD AND FRUIT QUALITY OF HAMLIN ORANGE TREES GROWN UNDER RAFAH CONDITIONS

 
This study wad carried out on mature Hamlin orange trees grown in Rafah orchard located at Northern Siani governorate. The experiment included spraying with urea at 0.5% with two forms of potassium phosphate, (potassium dihydrogen phosphate or dipotassium hydrogen phosphate) each at 1% or 1.5% twice (late May and early August) during 1997 and 1998 seasons.
Aim of The experiment was to show the effect of the sprayed materials on mineral content in leaves, yield and fruit quality.
Results revealed that spraying urea with different forms of potassium raised leaf N,P and K contents and increased yield/tree
Most treatments increased average fruit weight, volume, diameter and juice weight. T.S.S and T.S.S./acid ratio was only increased due to urea + dipotassium hydrogen phosphate in both concentrations. Different treatments decreased juice percentage and ascorbic acid (V.C) than the control in both seasons of this study.
The best results with respect to mineral status, yield and average fruit weight and volume of Hamlin orange trees were obtained due to spraying 0.5% urea + 1.5% dipotassium hydrogen phosphate twice in late May and early August. So, this treatment seems to be promising for Hamlin orange trees under this study.