This study aimed to evaluate the impact of a biosurfactant produced by Pseudomonas putida KT2440 on the efficiency of various chelating agents in enhancing soil nutrient availability and maize nutrient uptake in a calcareous soil. The research included both incubation and greenhouse experiments. In the incubation experiment, the effect of the biosurfactant, applied alone or in combination with citric acid, sodium citrate, humic acid, and EDTA, on the availability of phosphorus, iron, and zinc in the soil was investigated. In the greenhouse experiment, nutrient uptake and maize biomass production under biosurfactant treatment were compared with those of other chelating agents. Biosurfactant application significantly increased iron and phosphorus availability in the soil, with phosphorus levels rising fivefold compared to the control. However, the biosurfactant did not significantly enhance the effectiveness of the chelating agents. In the greenhouse experiment, maize treated with the biosurfactant showed a significant increase in biomass and nutrient concentrations, with iron, zinc, and phosphorus levels in plant shoots increasing by 2.13, 2.16, and 2.39 times, respectively, compared to the control. Citric acid and sodium citrate had no significant effect on nutrient availability. Humic acid did not increase maize yield. EDTA drastically reduced maize biomass. These findings suggest that biosurfactants have the potential to enhance nutrient availability in calcareous soils, reduce reliance on chemical fertilizers, and support the sustainable production of crops such as maize.

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