الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
This work was carried out during winter seasons of 2010/2011 and 2011/2012 at El-Khattara Agricultural Research Farm, Fac. Agric., Zagazig University, to study the effect of planting dates (30th Nov., 15th Dec. and 30th Dec.), plant spacings (7, 11 and 15 cm) and potassium fertilization rates (40, 80 and 120 kg K2O /fed.) on the productivity, quality and storability of onion grown in sandy soil. These treatments were arranged as split split- plot in a randomized complete block design with three replicates .Planting dates were randomly arranged in the main plots, plant spacings were randomly distributed in the sub plots and potassium levels were randomly arranged in the sub sub- plots. The interactions among planting date on 30th November, plant spacings at 7, 11 or 15 cm and 40,80 or 120 K2O /fed. recorded the highest bulb diameter and total dry weight / plant and enhanced bulb quality; i.e., DM%, TSS% and vitamin C. The interaction among planting date on 30th November and plant spacing at 11 or 15cm and K2O rates at 40, 80 or 120kg/fed. increased yield of grade 1. Moreover, the interaction among planting date on 30th November, planting space at 7cm, and K2O rates at 40, 80 or 120 kg/fed. increased yield of grades 3 and 4 as well as exportable, marketable and total yield/fed. compared to other triple interaction treatments. The interaction among late planting date (30th Dec.), plant spacings at 7, 11 or 15 cm and K2O rates at 40, 80 and 120 kg/fed. and the interaction among planting date on 30th Dec., planting distances at 7 or 11cm and K2O at 120 kg/fed. decreased weight loss and sprouting percentages during storage periods, respectively.