Halotolerant N-Fixing Bacteria Isolates for Increasing the Biochemical Activity, Total Bacteria Population, N-Uptake and Rice Seedling Growth

Abstract

Rice farming is hampered by saline soil, which contains a large amount of soluble salt. The high salt content inhibits plant growth and causes nitrogen nutrient deficiency, as well as sodium and chlorine ion poisoning. Beneficial microbes that have adapted to saline ecosystems (halotolerant) can reduce salinity’s impact on rice growth. Microorganisms known as halotolerant bacteria can survive in high salt environments by maintaining an osmotic balance. The use of halotolerant N-fixing bacteria (HNB) as biofertilizers is an attempt to boost nitrogen nutrients and rice plant productivity in saline land. The goal of this study was to see how effective HNB isolates were at increasing rice plant growth. The experiment was conducted in the greenhouse of Universitas Padjadjaran’s Faculty of Agriculture, using a randomized block design with 16 treatments (control, single, and consortia of inoculant) and was repeated three times. Rice seedlings were inoculated with HNB isolates and grown in a Fahraeus saline medium. The HNB consortium application increased plant height by 9.03 cm, root-shoot ratio by 0.92, IAA content by 0.475 g/mL, nitrogen content by 2.94%, and the total number of HNB isolates (Azotobacter, Azospirillum, Bacillus, and Stenotrophomonas) by 8.10x107 CFU/mL. Keywords: Biofertilizer, consortia inoculum, N-fixing bacteria, rice seedling