HARNESSING ACID- AND SALINITY-TOLERANT SYMBIOTIC NITROGEN-FIXING BACTERIA AND PGPR TO IMPROVE SOYBEAN GROWTH IN DEGRADED SOILS

Abstract

Soybean (Glycine max L.) productivity in degraded land is often hampered by acidity and salinity stresses that reduce nutrient availability and inhibit plant growth. This study aims to evaluate the potential of symbiotic nitrogen-fixing bacteria (BPN) and growth-promoting rhizobacteria (RPT) that are tolerant to acidic and saline conditions in enhancing soybean growth on degraded soils. The study was conducted in three stages: the first stage tested the acid tolerance of BPN and RPT isolates, the second stage tested the salinity tolerance of BPN and RPT isolates, and the third stage tested the biological activity of acid- and salinity-tolerant inoculants on black soybean plants. The results of the study at 28 days after planting (DAP) showed that the application of inoculants significantly increased shoot and root length, both under acidity and salinity stress. This increase was driven by the ability of bacteria to provide nitrogen, dissolve phosphate, and mitigate aluminum toxicity or osmotic stress caused by salt. Overall, the use of this functional microbial consortium proved effective as a biostimulant to improve soybean agronomic performance in degraded soils.