Effect of Different Nitrogen Plus Phosphorus and Sulphur Fertilizer Levels on Growth,Yield and Quality of Onion (AIlium cepa L.)

摘要

Field experiments were carried out for two consecutive seasons of 2009/2010 and 2010/2011 at the Experimental Station of National Research Centre in Nubaria region, El-Behira Governorate, Egypt, to find out the response of onion plants cv. Giza 20 to different fertilizer levels of nitrogen plus phosphorus (60 + 30 and 90 + 45 units/fed.) and three levels of sulphur (control, 200 and 400 kg S/fed.) on growth, yield and quality as well as uptake nutrients using an experimental design of split plot with three replications for each treatment. The obtained results revealed that all vegetative growth parameters and harvested bulb attributes as well as mineral and protein contents of onion significantly recorded the highest values, when supplied with nitrogen plus phosphorus at a higher rate of 90 + 45 units/fed. in both seasons of study, except for plant length, bulb diameter and harvested bulb length in the first season, in addition to harvested bulb length and diameter in the second season. Sulphur application at a rate of 400 kg S/fed. markedly enhanced all measured parameters of vegetative growth in the first season only except bulb diameter. While in the second season, there no clear trend was realized, where the highest values for vegetative growth parameters were fluctuated between sulphur application at rate of 200 and 400 kg S/fed. The highest values of the average weight of harvested bulb and bulb yield as well as bulb and neck dimensions (length and diameter) and Fe content in bulb tissues were significantly recorded when onion plant supplied by sulphur at rate of 400 kg S/fed. compared to all other treatments in both seasons, as well as K content in the second season only. The interaction between the two levels of nitrogen plus phosphorus fertilizer and three levels of sulphur had a significant difference effect on bulb diameter, leaves fresh weight and bulb and whole plant dry weight in the first season. As well as on fresh and dry weights of whole plant and its organs except neck dry weight and neck length and diameter in the second season. In the same respect, there was no significant interaction effect of nitrogen plus phosphorus and sulphur treatments on bulb yield, harvested bulb attributes and nutrient contents in both seasons except for length of bulb and neck in the first season and bulb dimensions (length and diameter) as well as K, Fe and Mn contents in the second season.