Effects of various vegetation patterns on soil nutrients recovery in Heidaigou coal mine

Artificial revegetation is a vital method of ecological recovery for damaged ecosystems. However, the assessment on the recovery effects of various vegetation patterns is still rare to date. In this study, the recovery situation of recliamed soil nutrients in Heidaigou opencast coal mine recovered for nearly 20-years was evaluated using various artificial vegetation patterns. The results showed that soil nutrients content was significantly affected by vegetation patterns. The contents of SOM, TN and NO3--N were significantly different in various soil depth while there was no significant difference for soil TP, TK and NH4+-N. Although SOM, TN and NO3--N assembled in the surface soil, artificial vegetation changed their vertical distribution properties compared with natural vegetation. Herbage vegetation with fabaceous plants was better than other vegetation patterns for soil nutrients recovery. Average SOM, TN and NO3--N within 50 cm soil depth had recovered to 63.9%, 57.8% and 184.8% of natural vegetation site after nearly 20 years recovery, the average level of SOM, TN and NO3--N within 30-50 cm soil depth even exceeded abandoned field. The results indicated that artificial revegetation was an effective measure to improve soil nutrients recovery, and herbage vegetation with fabaceous plants was the first choice to implement soil ecological recovery in the mine reclaimed land. Furthermore, SOM, TN and NO3--N could be used as an index to evaluate the effects of soil recovery in this mine region.