الفهرس 
REVIEW OF LITERATUREOnly 14 pages are availabe for public view
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Abstract
Rice crop (Oryza sativa, L.) is one of the most important and leading food crops of the world and the major stable food for over half of the world’s population. More important, it is the stable food in areas of high population density and fast population growth. Therefore, it is important to increase the productivity of rice yield to cover the increasing consumption needs. This problem had two solutions; first, horizontal increase by increasing the total cultivated area but it was faced by water shortage problem therefore, the Egyption government has tried to limit rice cultivation areas, second, the vertical increase by increasing the productivity of unit areas. A lot of efforts have been exerted in this regards by releasing new rice varieties with higher productivity and giving more attention to agriculture practices including fertilization that increase grain yield.
Nitrogen is considered a key element that manipulates the performance of the plants to some extent, especially cereal crops. It is beyond any doubt that the fertilization program of rice crop must have nitrogen on top of various nutrient elements, the amount of (N) required and management varies depending on variety, soil conditions, cultural practices, crop rotation and other factors.
In the past few years, a problem with the availability and prices of nitrogenous fertilizers appeared which increased production cost. This also led to not adding fertilizers in the proper time or reducing the amount of fertilizers which affected productivity, and causes a huge concern, in Egypt and around the world.
Utilization of biological N2 fixation (BNF) can decrease the application of mineral N fertilizers, reducing environmental risks (Raimam et al (2007) and Radwan et al (2008). Also, mycorrhiza fungi play a mejer role in whole plant nutrient balance by aiding in the uptake of limiting nutrients and maintaining the nutrient balance (Ning and Gumming, 2001). Using bio-fertilization or microbial inculcates to replace or increase the efficiency of chemical fertilizer partially or totally is effective in reducing the cost of crop production and maintaining the natural fertility of soil (Bassal et al, 1996).
The purpose of this investigation is to study the response of some rice cultivars to different plant spacing and bio nitrogenous fertilization, on some growth characters, yield components and grain yield as well as grain quality characteristics.