الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Recently, a great attention is paid in establishing concept of the associations between wheat plants and a variety of N2-fixing microorganisms. This phenomenon has entered the scientific scene arising from the prospects and the possibilities of their potentially application. . In this work, the soil based cyanobacteria inoculum (SBCI) was applied to wheat variety Giza 168 cultivated either in sandy soil (El-Ismailia Res. station) or calcareous soil (El-Nubaria Res. Station) in a greenhouse experiment under different levels of nitrogen to explore its influence on wheat yield and its components as well as on some soil properties of both sandy and calcareous soils. Results revealed that at heading wheat stage (75 days from sowing) inoculation with cyanobacteria improved the total N, P and K contents of wheat plants and enhanced the pigments content (Chl. a, Chl. b and Carotene) of wheat plants. Also, at harvest 75 % N + SBCI gave the highest wheat grain and straw yields, highest total NPK contents for both grains and straw. These results were not significantly differed from those recorded by 100 % N treatment. Inoculation with cyanobacteria increased the proportion of macro-aggregates with a corresponding decrease in the micro-aggregates in both tested soils. Inoculation with cyanobacteria increased both soil organic matter and water holding capacity percentages, while decreased the soil bulk density for both tested soils. Inoculation with cyanobacteria improved the soil chemical properties, soil biochemical properties and soil biological activity of both sandy and calcareous soils after wheat harvesting. Generally, it is of preliminarily prediction that cyanobacteria inoculation can save 25 % of the mineral nitrogen required for wheat cultivation. Also, it can ameliorate and improve the physical properties of the marginal and poor soils such as those of sandy and calcareous soils applied in the present study.