An investigation which includes microclimate

gangue physical and chemical properties

terrain

gangue moisture

and organism was carried out in 280 coal waste piles in Yangquan City

Shanxi Province.Microclimate of coal waste piles was hot and dry

and ground temperature was abnormal by spontaneous combustion of gangues.Temperature of sloping surfaces where partly had been burning was exceeded the normal temperature range for plant growth.Coal waste piles easily generated slope erosion due to their large slopes and lax accumulations.After surface gangues had been eroded

no soil adhered to plant roots and plant growth vigor gradually became weak.Compared with loess

gangues had poor water holding capacity and low available water capacity.Surface gangues lacked water supplements from lower layers

which affected plant growth directly.The pH value of ignited gangues declined

nutrient status of surface gangues was bad

and species and quantity of gangue microbe were small.Plant growth condition in the coal waste piles indicated that ground temperature

erosion condition

acid

and moisture were factors affecting vegetation restoration.Plants could not grow if ground temperature exceeded 50 ℃ or pH value was low than 5.Compared with the regions of 20% water moisture

vegetation coverage in the region of 15% water moisture declined by about 10%～20%.In the eroded areas

vegetation coverage declined by about 30%.