Abstract:The availability and translocation leaching of Mg were studied in the lab by soil column simulating test treated with Mg fertilizer, different amounts of biochar, organic fertilizer and lime. The results showed that applying additives increased pH values of the fertilized soil layers (0-15 cm). Applying Mg fertilizer, biochar, 50% required lime, 3.3 g/kg and 6.6 g/kg organic fertilizer increased significantly exchangeable Mg content in the fertilized soil layer, while applying 10 g/kg organic fertilizer, 100% and 200% required lime decreased it, and exchangeable Mg content in the topsoil layer ranged from 14.61 to 126.03 mg/kg. Appling organic fertilizer and lime enhanced the migration ability of Mg. The content of exchangeable Mg in soil layer (15-50 cm) without fertilizer additive accounted for 64%-86% of the total soil column, while only 62% in the control treatment. Mg leaching with applying biochar was the highest, and it was proportional to the applied amount of biochar, while applying lime reduced Mg leaching, which was up to 7.95% lower than CK. Applying organic fertilizer obtained the highest leaching rate (46.58%) and the lowest fixed rate (49%) of Mg. Applying biochar got the maximum released amount of Mg (507.4 mg), which was proportional to the applied amount of biochar. The released amount of Mg with applying lime and organic fertilizer was 101-156 mg. In conclusion, the released amount of Mg and the available Mg content in soil were the highest with applying biochar while the leached amount and the leaching rate of Mg with applying lime were the lowest.