The interactive effects of arbuscular mycorrhizal fungi and rhizobacteria on the growth and nutrients uptake of sorghum in acid soil

Jaka Widada^1*, Dolly Iriani Damarjaya², and Siti Kabirun¹

¹Laboratory of Soil and Environmental Microbiology, Department of Soil Science, Gadjah Mada University, Yogyakarta, Indonesia; ²Department of Soil Science, Sriwijaya University, Palembang, Indonesia

Email: jwidada@lycos.com

The inoculation effects of arbuscular mycorrhizal fungi (AMF) or/and rhizobacteria, (phosphate-solubilizing bacteria, PSB; N₂-fixing bacteria, NFB; and siderophore-producing bacteria, SPB) on the growth and nutrients uptake of sorghum (Sorghum bicolor) were studied in acid and low availability phosphate soil. The microbial inocula consisted of the AMF Glomus manihotis, PSB Pseudomonas sp., NFB Azospirillum lipoferum, and SPB fluorescent pseudomonad. The inoculation of either AMF or each rhizobacterium improved the plant dry weight and nutrients uptake such as N, P, Fe, and Zn. Dual inoculation of AMF and each rhizobacterium yielded the higher of plant dry weight and nutrients uptake compared to the single inoculation. Dual inoculation of AMF and PSB, AMF and NFB, AMF and SPB increased plant dry weight by 112, 64, and 60 times higher compared to the uninoculated plant, respectively. The rhizobacteria also improved plant colonization by AMF. These results indicated that the interaction of AMF and the selected rhizobacteria has a potential to be developed as biofertilizers in acid soil.