Phosphate-solubilizing and nitrogen-fixing bacteria are crucial in increasing soil fertility and restoring soil properties damaged by salinity and other abiotic environmental factors. The presented study aims to explore and identify the morphological characteristics of phosphate-solubilizing and nitrogen-fixing bacteria in saline soil. This study took place from August until November 2022 in the field and laboratory of the Faculty of Agriculture, Universitas Muhammadiyah Sumatera Utara, Medan, Indonesia. Isolation of potential microbes proceeded to characterize phosphate-solubilizing and nitrogen-fixing bacteria. Sampling began with the soil planted with rice and palm oil at the sampling location. Morphological parameters observed were color, form, margin, surface, and elevation of pure colonies. The result showed that exploring various species in saline soil revealed 19 colonies and 14 cells of phosphate-solubilizing bacteria and 16 colonies and 14 cells of nitrogen-fixing bacteria. The pure colonies of the phosphate-solubilizing and nitrogen-fixing bacteria showed differences in the morphological characteristics, i.e., color, form, margin, surface, and elevation. The potential microbes obtained sought to increase soil fertility and crop production.

Keywords: Phosphate-solubilizing bacteria, nitrogen-fixing bacteria, morphological characteristics, saline soil

Key findings: Exploration and identification of morphological characteristics is a must action to analyze potential microbes in depth to improve the quality of saline soils to increase crop productivity.