Effectiveness of Rhizobium bacteria as biofertilizer on the growth of soybean (Glycine max L) in the greenhouse

Plant Growth-Promoting Rhizobacteria (PGPR) boost plant growth; selecting an effective PGPR is key for biofertilizers. The goal of this investigation was to acquire Rhizobium isolates for biofertilizers. On YEMA media, Rhizobium was isolated from 21 East Kalimantan soil samples. Using TSB (IAA hormone), Pikovskaya (phosphate solubilizing), Skim Milk Agar (Protease), and NFB (N-fix), the PGPR activity of pure Rhizobium isolates was determined. High-activity isolates were then tested in a greenhouse for their capacity to boost soybean growth (Glycine max L). Rhizobium bacteria ranged from 15 to 95 x 105 CFU/g soil; 21 isolates all contained Rhizobium bacteria. 11 isolates produced IAA hormone, 11 produced protease enzymes, 16 fixed nitrogen, and 10 solubilized phosphate. A pink colour around the colony after reacting with Salkowski’s reagent was used to identify IAA-producing bacteria. "Clean zone" indicates a positive response for protease and phosphate-solubilizing bacteria. Rhizobium isolates that make the NFB medium blue have N-fixing activity. The greenhouse tests showed that the dry weight of the canopy was highest in plants inoculated with isolate 2 KY (2.79 g), the dry weight of the root was highest in plants inoculated with isolates 3 KY, 9 KY, and 15 KY (0.88 g), and the dry weight of total plants was highest in plants inoculated with isolate 15 KY (4.11 g). Isolate 15 KY had the best growth outcomes.