Purpose <p>The study aimed to evaluate liming materials combined with biochar and organic amendments for surface and subsoil acidity amelioration.</p> Methods <p>A soil column incubation study was conducted under laboratory conditions for 12 weeks using the southern laterite soils (AEU-8) of Kerala, at College of Agriculture, Vellayani. The 17 treatments studied included farmyard manure (FYM) at 20 t ha^− 1, humic acid (HA) at 10&#xa0;kg ha^− 1, poultry manure (PM) at 1 t ha^− 1 and coconut frond biochar (CFB) at 10 t ha^− 1 each in combination with lime, dolomite, calcium silicate (CS) or phosphogypsum (PG) at lime requirement (LR) and a soil alone control.</p> Results <p>After 12 weeks of incubation, soil pH was highest under CFB at 10 t ha⁻¹ with lime as per LR (6.7 at 0–15&#xa0;cm), FYM at 20 t ha⁻¹ with CS as per LR (5.8 at 15–30&#xa0;cm), and CFB at 10 t ha⁻¹ with PG as per LR (5.16 at 30–60&#xa0;cm). Application of CFB at 10 t ha⁻¹ with CS as per LR significantly lowered exchangeable Al³⁺ (0.16, 0.16, 0.42 meq 100&#xa0;g⁻¹) and H⁺ (0.11, 0.13, 0.21 meq 100&#xa0;g⁻¹) while enhancing Ca²⁺ (792.46, 521.68, 498.69 meq 100&#xa0;g⁻¹), and CFB at 10 t ha⁻¹ with dolomite as per LR maintained higher Mg²⁺ values (103.60, 90.31, 89.05 meq 100&#xa0;g⁻¹) across soil depths.</p> Conclusion <p>Among the tested combinations, the application of CFB at 10 t ha^− 1 with CS ad per LR most effectively ameliorated subsoil acidity, followed by the treatment CFB at 10 t ha-1 with dolomite as per LR.</p> Graphical abstract <p></p>