Integration of lime and GA3 to enhance growth and leaf mineral composition of stevia (Stevia rebaudiana) in acidic soils of the northern region of Bangladesh

Stevia rebaudiana , a natural zero-calorie sweetener, faces cultivation challenges in the acidic soils (pH < 5.5) of northern Bangladesh. While lime corrects soil acidity and gibberellic acid (GA₃) promotes plant growth, their interactive effects on stevia have not been previously investigated. A field experiment (RCBD, 12 treatments: 4 lime rates × 3 GA₃ concentrations), 36 plots (2 m × 2 m) with 3 replications evaluated morphological traits, leaf mineral composition (N, P, K, S, Ca, Mg, Zn), and post-harvest soil nutrient availability. Plant height ranged from 90.62 cm (T₁) to 96.12 cm (T₆; 0.5 t ha⁻¹ lime + 250 ppm GA₃). T₉ (1.0 t ha⁻¹ lime + 250 ppm GA₃) produced the highest primary (12.38) and secondary (34.84) branches, and maximum leaf nitrogen (1.97%) and calcium (1.70%). Factorial ANOVA revealed significant lime × GA₃ interactions for plant height ( p < 0.01), leaf number ( p < 0.05), and nutrient content (N, Ca, Mg; p < 0.05). Post-harvest soil pH improved from 5.13 to 6.67 (T₁₂), though validation is needed. PCA confirmed clustering of growth-promoted treatments (T₆, T₉). Combined lime and GA₃ application significantly enhanced stevia growth and leaf mineral composition in acidic soils. T₉ (1.0 t ha⁻¹ lime + 250 ppm GA₃) was most effective for branching and nutrient accumulation. This integrated approach shows promise for stevia cultivation in acidic soils, though future research should include steviol glycoside analysis and multi-location trials to validate these findings.