Purpose <p>This work aims to investigate phosphate adsorption by activated dolomite through in-batch experiments and an in-situ soil amendment application using activated dolomite to address phosphorus fertilizer leaching and low phosphorus-use efficiency in acidified soils.</p> Materials and methods <p>Activated dolomite (A-DO) was prepared by high-temperature calcination of dolomite mining waste. Batch adsorption experiments combined with characterization analyses were conducted to elucidate its phosphate adsorption characteristics and mechanisms in aqueous solution. Soil column leaching experiments were further performed to evaluate its effects on phosphorus availability in acidified soils.</p> Results and discussion <p>The results showed that phosphate adsorption by A-DO in aqueous solution followed the pseudo-second-order kinetic model (R² = 0.999) and the Freundlich isotherm model (R² = 0.919), indicating a heterogeneous, multilayer chemisorption process. X-ray photoelectron spectroscopy analysis further revealed that the dominant mechanism involved precipitation between Ca²⁺ and Mg²⁺ released from A-DO and phosphate species. Soil column leaching experiments demonstrated that, at the optimal application rate of 6&#xa0;g kg^− 1, A-DO reduced phosphorus leaching losses by 88% and increased soil available phosphorus by 20%. These improvements were attributed to the capacity of A-DO to ameliorate soil acidity, weaken aluminum-induced phosphorus fixation, and enhance organic-matter-driven phosphorus mineralization, thereby effectively increasing soil available phosphorus.</p> Conclusions <p>In summary, A-DO, as a high-efficiency and low-cost environmental functional material, shows strong application potential for the value-added utilization of solid wastes and the regulation of phosphorus fertilizers in agricultural systems.</p>