Non-ammonium leaching is an important way for the green development of ion-adsorption rare earth ores. However, the effects of different non-ammonium leaching agents on soil ecological environment remains unclear. Taking the raw ore as the blank control, we investigated the differences of the effects of three non-ammonium leaching agents (Magnesium sulfate, calcium chloride and calcium chloride-aluminum sulfate) and ammonium sulfate on soil physicochemical properties, microbial quantity and enzyme activity through indoor column leaching, and discussed the main limiting factors of tailings soil vegetation restoration under different leaching agents. Results showed that the soil properties of tailings leached by non-ammonium agents are significantly different from those of ammonium sulfate. Compared with ammonium sulfate leaching agent, non-ammonium leaching reduces the loss of potassium, brings rich calcium or magnesium elements, and improves the activity of acid phosphatase in tailings soil. However, the number of culturable bacteria and soil basic respiration after non-ammonium leaching are lower than those of ammonium sulfate. After leaching by calcium chloride and calcium chloride-aluminum sulfate, the microbial biomass carbon of tailings was significantly lower than that of ammonium sulfate. The raw ore soil is poor in nutrients and lacks nutrients such as organic matter, nitrogen, available phosphorus and available potassium. Non-ammonium leaching leads to the imbalance of the calcium-magnesium ratio in tailings soil, which is also one of the limiting factors of vegetation restoration. In addition, the residue of aluminum after calcium chloride-aluminum sulfate leaching is a potential limiting factor for tailings vegetation restoration.
 

ion-adsorption rare earth ore,non-ammonia leaching,microorganisms,limiting factors of vegetation restoration