Using Various Forms of Potassium (K) Fertilizers to Improve the Yield and Fruit Quality of Washington Navel Orange under Qalyoubia Governorate Conditions

The obtained data revealed obviously that all studied fertilization treatments in this study fruiting aspects and yield production parameters i.e., (fruit set, fruit retention, average fruit weight (g), number of fruits per tree, yield/tree either in kg or number of fruits per tree and yield as ton per feddan) whereas, decreased percentage of fruit drop during the two experimental seasons. Moreover, fruit quality i.e., physical properties average fruit weight (g.) (peel thickness, polar diameter, equatorial diameter, fruit shape index, juice weight (g) and juice %) and chemical characteristics (TSS, total acidity %, TSS/acid ratio, total sugars % and vitamin C “mg/100 g J.W.” were improved generally from the standpoint of statistic by all investigated fertilization treatments, while leaf fruit shape index did not responded from the standpoint of statistic to any fertilization treatments, since the response was completely absent and the differences were insignificant during the two seasons of study.Undoubtedly, it could be concluded that, all investigated fertilization treatments under study resulted in a significant and beneficial effects on most parameters of Washington navel orange trees. However, the treatment of (potassium acetate, carboxyl and phosphate) combined with CaB exhibited statistically the best and the most effective treatments for increasing and improving both productivity and fruit quality (physical and chemical) properties of Washington navel orange trees.