الفهرس 
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Abstract
A pot experiment was conducted at the Experimental Station Farm, Faculty of Agriculture, Mansoura University during the winter season of 2013/2014 to investigate the effect of phosphorus, nitrogen and copper fertilization on growth, yield, quality and nutrients uptake of onion (Allium cepa L.). The effect of phosphorus fertilizer levels on growth characters (fresh and dry weights of onion plant ”g”, plant height ”cm”, number of leaves plant-1 and chlorophyll a, chlorophyll b and total chlorophylls in onion leaves ”mg g-1 fresh weight”), yield attributes (bulb fresh and dry weights at harvest stage ”g”, bulb diameter ”cm” at harvest stage, neck diameter ”cm” at harvest stage and plant height ”cm” at harvest stage(and chemical analyses (nitrogen, phosphorus, potassium and protein percentages in onion leaves after 50 days from transplanting, nitrogen, phosphorus and potassium uptakes by onion plants after 50 days from transplanting, nitrogen, phosphorus, potassium and protein percentages in onion bulbs at harvest stage, nitrogen, phosphorus and potassium uptakes by onion plants at harvest stage, copper percentage and copper uptake in onion bulbs at harvest stage and sulfur volatile oil percentage in onion bulbs at harvest stage) was significant in the growing season. There were substantial differences in all studied characters among various studied phosphorus fertilizer levels i.e. 0, 50 and 100 kg calcium super phosphate fed-1 in the growing season. Since, fertilizing onion plants with the highest level of phosphorus fertilizer (100 kg calcium super phosphate fed-1) produced the highest values of the previously mentioned characters in the growing season. On the other wise, control treatment (without phosphorus fertilization) gave the lowest values of these characters in the growing season. The effect of copper fertilizer levels as foliar application on growth characters (fresh and dry weights of onion plant ”g”, plant height ”cm”, number of leaves plant-1 and chlorophyll a, chlorophyll b and total chlorophylls in onion leaves ”mg g-1 fresh weight”), yield attributes (bulb fresh and dry weights at harvest stage ”g”, bulb diameter ”cm” at harvest stage, neck diameter ”cm” at harvest stage and plant height ”cm” at harvest stage( and chemical analyses (nitrogen, phosphorus, potassium and protein percentages in onion leaves after 50 days from transplanting, nitrogen, phosphorus and potassium uptakes by onion plants after 50 days from transplanting, nitrogen, phosphorus, potassium and protein percentages in onion bulbs at harvest stage, nitrogen, phosphorus and potassium uptakes by onion plants at harvest stage, copper percentage and copper uptake in onion bulbs at harvest stage and sulfur volatile oil percentage in onion bulbs at harvest stage) was significant in the growing season. With regard to the interactions between the studied factors, great deals of them were statistically significant in most cases. The interaction among phosphorus fertilizer levels × nitrogen fertilizer levels × copper fertilization as foliar application had a significant effect on fresh weight of plant (g) after 50 days from transplanting (at thinning stage), plant height (cm) of onion plant after 50 days from transplanting (at thinning stage), number of leaves per onion plant after 50 days from transplanting (at thinning stage), bulb fresh weight (g) after 90 days from transplanting (at harvest stage), phosphorus and potassium percentages in onion leaves after 50 days from transplanting (at thinning stage), phosphorus uptake (mg plant-1) by onion plants after 50 days from transplanting (at thinning stage), nitrogen, phosphorus, potassium and protein percentage percentages in onion bulbs after 90 days from transplanting (at harvest stage), nitrogen, phosphorus and potassium uptake (mg plant-1) by onion plants after 90 days from transplanting (at harvest stage), copper percentage in onion bulbs after 90 days from transplanting (at harvest stage), copper uptake (mg plant-1) by onion bulbs after 90 days from transplanting (at harvest stage) and sulfur volatile oil percentage in onion bulbs after 90 days from transplanting (at harvest stage). It can be concluded that fertilizing onion plants with 100 kg calcium super phosphate fed-1 and 150 kg N fed-1 in addition foliar spraying with 50 ppm Cu in the form of CuSO4 at three time in order to maximizing its growth, yield and its components, quality and nutrients uptake under the environmental conditions of Mansoura district, Dakahlia Governorate, Egypt.