Impact of humic acid, different phosphorus forms, and plant growth promoting rhizobacteria (PGPR) producing or non-producing exopolysaccharides on microbial soil enzymes and peanuts yield.

This study aimed to study PGPR features. Additionally, a field experiment was carried out at the Ismailia Agricultural Research Station in Egypt during the summer season of 2022 to evaluate the interaction among the more potent PGPR, humic acid, and phosphorus forms, on microbial soil enzymes of peanut and it is correlation with yield increasing . Results emphasized that the dehydrogenase (DHA), phosphatase (P-ase), and nitrogenase activity (N-ase) values with all treatments at 60 days were higher than at 30 days. Also, the activity values of the three enzymes were superior in peanut plants treated with humic than in untreated plants.Regarding the dehydrogenase enzyme activity, PGPR with humic acid and 100% rock phosphate (RP) gave the highest enzyme activity, while the highest enzyme activity in the case of PGPR1 was observed with treatment that was treated with humic acid and single super phosphate100% (SSP).Whilst, PGPR gave the maximum records of P2-ase when peanut plants were treated with the combination of SSP (50%) + RP (50%), Otherwise, PGPR1 gave the highest values when peanut plants were treated with RP (100%). Additionally, the high significant values of N-ase activity were observed in peanut nodules that were inoculated with PGPR combined with humic and both SSP (100%) and RP (100%) individually. While treated peanuts with the combination of SSP (50%) + RP (50%), PGPR1 gave the highest significant values of N-ase activity. Finally, inoculation with PGPR or PGPR1 +humic substances with 50% SSP+ 50% RP resulted in significant increases in peanut seed yield.