Combined application of alkaline materials and organic fertilizer accelerates nitrification process of rare earth mining soil

Ammonia nitrogen (NH4+-N) pollution is a widespread problem in the tailing soils of ion-adsorption rare earth deposits in southern China, since large amount of NH4+-N was used to extract rare earth element (REE) during the mining. However, there is no feasible strategy to remove excessive soil NH4+-N and alleviate soil acidification up to now. Herein, we developed an effective approach to promote the nitrification of soil NH4+-N, and then remove soil NO3--N directly.