Peanut being a leguminous crop is capable of fixing atmospheric nitrogen. The present investigation had been carried out in order to study and evaluate the efficiency of both liquid and solid inoculum of Bradyrhizobium ssp (N2-fixing bacteria) alone or with plant growth promoting rhizobacteria (PGPR); Azotobacter chroococcum DSM 2286, as co-inoculation to reduce the negative impact of salinity of irrigation water (Nile Water (563 mg L-1) (W1), Groundwater artesian well, about 1000 mgL-1 (W2) and Groundwater artesian well about 2000 mgL-1 (W3), were collected from cultivated regions of Sadat city.) on peanut plants grown in cultivated sandy soils. Nodulation, fresh and dry weights of the growing plants and their elemental composition, mainly contents of nitrogen, phosphorus, potassium, manganese, zinc and Iron, yield, yield components as well as quality traits of the seed and oil of two peanut cultivars grown in sandy soils were determined. The biofertilizers inoculation treatments as follows: 1-Control treatments (without any biofertilizers inoculation). 2- Inoculation by solid Bradyrhizobium alone. 3-Inoculation by liquid Bradyrhizobium alone. 4- Co-inoculation: by solid Bradyrhizobium + PGPR (Azotobacter chrococoum), and 5- Co-inoculation: by liquid Bradyrhizobium fertilization + PGPR (Azotobacter chrococoum).
It could be concluded that inoculation by liquid Bradyrhizobium + Azotobacter chroococcum seems to be the recommended treatment for producing optimum seed and straw yield and other parameters studied. Likewise it achieved the least production costs, also reducing the harmful effects of salinity of soil and/or irrigation water. These in turn reflect an increase in dry matter yield and after that pod, seed and straw yield. However, this approach could be explored as an effective strategy with least production costs to improve salt tolerance index in peanut plants under drip irrigation system in newly reclaimed soils in Egypt.