ISOLATION AND SCREENING OF BACTERIA WITH PLANT GROWTH PROMOTION TRAITS FROM IRON SAND SOILS OF CENTRAL JAWA SOUTH COAST

Abstract

Isolation and screening of bacteria with plant growth-promoting traits from iron sand soils have been conducted. The traits examined included nitrogen fixation, IAA production, phosphate and potassium solubilization, and siderophore production. The physical and chemical properties of the iron sand soil of Central Java's south coast showed that air and soil temperatures were 31–39°C and 29–35°C, pH levels ranging from 6.5 to 7.8, and humidity levels between 15% and 100%. Sixteen bacterial isolates were identified, with population densities ranging from 5.0 x 10² to 3.5 x 10⁵ CFU. g^-1 of soil. Out of these, 11 isolates demonstrated nitrogen-fixing abilities. Two isolates, PS2Y2 and KS1C4, produced IAA at concentrations of 20.6 ppm and 11.73 ppm, respectively. All isolates were capable of solubilizing phosphate, with solubilization index (SI) ranging from 1.09 to 2.81. One isolate, CS1P1, exhibited a strong ability to solubilize potassium, with an SI value of 6.39. Additionally, three isolates PS3Y4, KS1K1, and CS1P1 were able to produce siderophores.