الفهرس 
AcknowledgmentOnly 14 pages are availabe for public view
 |  | from | 236 |  |  |
| | | from | 236 | | |
Abstract
The study aimed to isolate free living nitrogen fixers and to evaluate their tolerance to salinity stress in the desert environment where they will eventually be used. The ultimate goal of the study was to reduce the usage of N2 fertilizers because of their high cost as well as the health hazards encountered because of the extensive use of the nitrogenous compounds in the environment. The study reviewed also soil salinity problems in Egypt and the effect of salinity on diazotrophs.
The main findings and conclusions of the present study are summarized under the following topics:
and
i. Bacterial isolation characterization
identification
Isolation of free living diazotrophs from a natural habitat i.e. from sand dunes and salt marches, 53 km west of Alexandria yielded 21 strains, 8 of which were Azotobacter, 7 of Azospirillum and 6 of Klebsiella. They were identified using morphological and biochemical characters.
2. Distribution of diazotrophs in soil A. Soil analysis
The data revealed a slight variation in carbonate, bicarbonate content; pH and cation/chloride ratio (CCR).