This study aims to observe the efficiency of probiotic inoculants on growth, soil fertility, and production of brown midrib (BMR) sorghum mutant lines. The experimental using a Randomized Block Design of four treatments and four blocks, P0: manure + (N, K, 0% P) + probiotic; P1: manure + (N, K, 50% P) + probiotic; P2: manure + (N, K, 75% P) + probiotic; P3: manure + (N, K, 100% P) without a probiotic (control). The dose of cow manure fertilizer is 10 tons/ha, and the doses of N, P, and K fertilizers are 120 kg/ha, 90 kg/ha, and 60 kg/ha, respectively, from urea, triple superphosphate (TSP), and potassium chloride (KCl). Parameters observed were plant morphology, biomass production, nutrient and fiber fraction content, and soil fertility. The treatment had no significant effect (P>0.05) on stem diameter, leaf length, and width, soil pH, fresh and DM production, the number of leaves, plant height, stem:leaf: panicle ratio, colony PSB, soil P-available, fiber and nutrient fractions of sorghum whole plant. The conclusion is that applying probiotics with lower phosphate fertilizer in sorghum cultivation produces growth, forage production, nutrition and fiber fraction content, and P-available and colony PSB, like 100% P fertilizer application. Probiotic bacteria could be applied as phosphate-solubilizing bacteria and reduce the application of P fertilizer on BMR sorghum in ultisol.