الفهرس 
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Abstract
Biofertilizers are microorganisms that help plant growth through the interaction of plant roots with them when added to cultivated soil. They are environmentally and sustainably sources for plants growth, an alternative to chemical fertilizers that have an impact on environmental pollution, whether it is in soil or water.
Many benefits are achieved when using biofertilizers including: restoring the balance of soil microbes and revitalizing the vital processes in it, helping to increase soil fertility by providing essential nutrients for plant growth, rationalizing the use of chemical fertilizers and reducing environmental pollution, increasing productivity and quality of growing plants.
The study was conducted as follows:
1. Isolation and purification of two nitrogen-fixing BGA from desert soil.
2. 16S rRNA gene sequencing for BGA isolates.
A) Chamomile field experiment (In vivo):
3. Inoculum preparation for conducting a field experiment on chamomile plant.
4. Applying different inocula for chamomile plant.
Summary
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5. Sample collection and preparation.
6. Statistical analysis.
B) Isolation, characterization, and identification of BGA cultivable AHB (In vitro):
7. Isolation and purification of AHB attached to the two BGA strains.
8. Qualitative assays for the cultivable AHB regarding plant growth-promoting activities (PGPAs) such as:
• Nutrient availability (Direct mechanism)
• Biocontrol agent (Indirect mechanism)
9. 16S rRNA gene sequencing for the promising multifunctioning bacteria.
The results can be summarized as follows:
1. By using 16S rRNA gene identification, two BGA strains isolated from desert soil were identified as Anabaenopsis circularis strain AnHu and Nostoc sp. strain NoHu with accession numbers OP394177 and OP364183, respectively.
2. Two BGA strains, AnHu and NoHu, were introduced to chamomile plants compared with positive and negative control.