A field experiment was carried out in the farm of faculty of Agriculture, Mansoura University, Mansoura, Egypt during the winter season of 2016 to study the effect of bio-fertilization under different level of nitrogen (75% and 50% of the full dose) on the growth and yield of wheat plant. Obtained results showed that the microbial inoculation leads to a significant increase in growth parameters (plant heights, number of tillers, leaves and dry weights). Also, microbial inoculation leads to a significant increase in NPKcontents as responded to all treatments under investigation in all stages of plant growth. The obtained results show a significant increase in yield parameters and its components (spike length, spike weight , number of grains / spike, weight of 1000 grains, grain and straw yield and NPK contents in grains and straw) as affected by microbial inoculation. The treatment T 9 (Az. chroococcum + K. oxytoca + 75 % dose of N) gave the highest value of grains and straw yield (19.61 and 3.13 ton/fed., respectively) with an increase by 21.87% and 19.01%, respectively. Also, the bio-fertilization has a pronounced increase in microbial count in comparison with the mineral fertilization. The present study recommend by the possibility of using the dual bacterial inoculum which containing Azotobacter chroococcum MF135558 and Klebsiella oxytoca MF135559 in the presence of 75% dose of N for enhancing growth and yield of wheat plants and reduce chemical fertilizers usage.

Rhizobacteria (PGPR) for its antagonist activity and suppression of Rhizoctonia solani AG2-3 causal agent of damping-off disease in soybean plant. Strains of Bradyrhizobium japonicum 110, Bacillus megaterium var. phosphaticum B6, Methylobacterium aminovorans ML3, M. rhodinum ML12, and Trichoderma viride 1433 species were used in the present study. In vitro, all tested strains showed a notable ability to inhibit mycelial growth of R. solani on different growth media. While, T.viride and M. rhodinum showed the highest rate of antagonism against R. solani. In vivo, in generally, PGPR treatments notably decreased damping-off and increased healthy plants, as compared to the control (infested soil). As compared to the uninoculated NPK fertilized control, higher growth parameters for shoot and root dry weight (g plant-1), number of nodules and dry weight of nodules (mg plant-1), chlorophyll content and NPK % of shoot and root, were recorded for the T 11 (inoculation with B. japonicum 110 + M. aminovorans ML3 + B. megaterium var. phosphaticum B6 + T. viride) and T 12 (inoculation with B. japonicum 110 + M. rhodinum ML12 + B. megaterium var. phosphaticum B6 + T. viride) treatments. Seeds yield of soybean plants attained higher values with all tested treatments. The obtained results of PGPR bacterial effects on damping-off disease and growth parameters of soybean recommend their use as an alternative tool rather than chemical fungicides. Such biocontrol approach should be included in the integrated management programs.

Nitrogen (N), Phosphorus (P) and Potassium (K) are the major essential macro-nutrients for plants. The ability of soil bacteria to provide available forms of these nutrients to plants is an important feature in the bacterial strain used as a biofertilizer. In this study, fifteen isolates of Azotobacter spp were isolated. The efficiency levels of the N 2 -fixation were tested, the isolates reduced acetylene at rates of 6.348 -1381.023 nmoles C 2 H 4 /ml/day. The most active isolate was No. AZ 8 that identified as Azotobacter chroococcum MF135558. Twenty-one phosphate-solubilizing bacteria (PSB) were isolated and solubilization efficiency % (SE%) of each isolate was determined by spot inoculation technique. Five isolates (PSB 3, PSB 7, PSB 8, PSB 12 and PSB 14) were chosen due to their high solubilization efficiency % (SE%) 182. 35, 173.33, 222.22, 170.00 and 194.11 %, respectively. The five P-solubilizing bacteria were tested for their ability to solubilize P from tri-calcium phosphate and rock phosphate in liquid Pikovskaya's medium. The highest quantity of released phosphorus in actively growing culture was 36.52 mg/100 ml after 28 days of incubation and 1.095 mg/100 ml after 3 days of incubation on tri-calcium phosphate and rock phosphate, respectively by isolate PSB 14 which was identified as Klebsiella oxytoca MF135559. Five isolates of K-releasing bacteria (KRB) were isolated on Alexandroov's medium and were tested to release K from mica-muscovite. All the tested isolates can release potassium from mica but not in equal efficiency. The most efficient isolate namely KRB-2 could release 7.05 ppm after 6 weeks of incubation. It was identified as Rhizobium pusense MF135560.

A FIELD experiment was carried out on the farm of Faculty of Agriculture, Mansoura University, Mansoura, Egypt during the winter season of 2016 to study the effect of bio-fertilization under different level of nitrogen and potassium (75% and 50% from the full dose) on the growth and yield of Onion plants. The obtained results showed that the microbial inoculation leads to a significant increase in growth parameters (foliage heights, number of leaves and dry weights). As well as NPK-contents as responded to all treatments under investigation in all stages of plant growth. The same trend was observed in yield parameters (bulb weights, total bulbs yield, Total soluble solids%, Dry matter% and NPK contents in bulb tissues). The treatment T4 (A. chroococcum + 75 % dose of NK) gave the highest total yield with an increase by 6.19% over the control. Also, the bio-fertilization has a pronounced increase in microbial count in comparison with the mineral fertilization. The obtained results of PGPR effects on growth parameters and yield of onion recommend their use as an alternative tool to reduce chemical fertilizers.

A set of six rice field inoculation trials was selected at two governorates in Egypt located at the Nile delta. These study was conducted to investigate the response yield components of three Egyptian rice varieties (Sakha 101, Giza 177 and Giza 178) to inoculation with three bacterial strains (Rhizobium leguminosarum bv. trifolli (RH) strain E11, Anabaena sp. strain ERC102 and Pseudomonas stutzeri strain ERP1) and their combination in the presence of three levels of nitrogen (48,96 and 144 kg N/ha.). The results were obtained from means of yield parameters calculated all over the six experiments. The results show that increasing with inoculation in paddy yield , straw yield(15.26 ton/ha.), harvest index rang is within 33.13% and agronomic Nuse efficiency compared with non-inoculated counterpart. The results of the agronomic N-use efficiency in the six experiments indicated that biofertilization can benefit grain production and then reduced agronomic N-use efficiency with increasing fertilizer-N doses. Finaly , the results concluded that the inoculation with bio-agents can reduce the need for additional fertilizer-N application to achieve and consequently higher grain yield.