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International Journal of Agronomy
Volume 2011, Article ID 316856, 6 pages
Research Article

Effects of Nitrogen Fertilization and Soil Inoculation of Sulfur-Oxidizing or Nitrogen-Fixing Bacteria on Onion Plant Growth and Yield

1Agricultural Microbiology Department, National Research Centre, Cairo 12311, Egypt
2Soil and Water Use Department, National Research Centre, Cairo 12311, Egypt
3United States Department of Agriculture-Agricultural Research Service, Vegetable and Forage Research, Prosser, WA 99350, USA

Received 25 June 2011; Revised 9 September 2011; Accepted 3 October 2011

Academic Editor: Ravindra N. Chibbar

Copyright © 2011 Nemat M. Awad et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


A field experiment was conducted in a newly reclaimed soil at El-Saff region, El-Giza Governorate, Egypt to study the effects of different rates of nitrogen (N: 62 to 248 kg ha-1) with or without soil inoculation of sulfur- (S-) oxidizing bacteria (SoxB) and combined inoculation of SoxB and N-fixing bacteria (NFxB) on yield, quality and nutritional status of onion (Allium cepa L., “Giza 20”). Elemental S at 620 kg ha-1 was applied to all treatments. Application of N at 62, 124, and 248 kg ha-1 rates increased onion yield, plant height, and N uptake by 28 to 76%, 32 to 53%, and 61 to 145%, as compared to those of the plants that received no N. Inoculation of SoxB at various N rates increased onion yields by 47 to 69% and N uptake by 76 to 93%, as compared to those of the plants which received the respective rates of N but no SoxB inoculation. Inoculation with SoxB and NFxB increased onion yield by 221%, plant height by 62%, and N uptake by 629%, as compared to those of the plants grown without inoculation and no N applied.