Sustainable Mining and Metallurgy

In order to understand the changes of soil acidification and nutrient distribution at different slope positions of extremely acidified waste dump,taking three typical waste dumps as the research object in Xinshan Area of Dabaoshan Mine in Guangdong Province, the changes of soil pH and net acid generation test, and the distribution differences of soil organic matter (SOM), total nitrogen (TN), total phosphorus (TP), total potassium (TK), available nitrogen (AN), available phosphorus (AP) and available potassium (AK) at different slope positions were analyzed. The results showed that:(1) The pH value range of 0~100cm layer at the slope toe of the waste dump was 1.96~3.76, which meant the soil was strongly acidic. The acid production capacity of soil was medium or high in 0~20cm layer, which had the trend of slope middle ＜ slope top ＜ slope toe;(2) The average content of SOM in 0~20cm soil layer had the trend of slope toe ＞ slope middle ＞ slope top, and the variation ranges were 0.24~2.32g/kg, 0.53~1.83g/kg and 1.28~1.55g/kg, respectively;the average content of TN had the trend of slope toe ＞ slope top ＞ slope middle, the higher slope toe was 0.25g/kg; the average contents of TP and TK were high, which were 1.00g/kg, 1.02g/kg, 0.94g/kg and 44.74g/kg, 48.59g/kg and 47.81g/kg at the slope top, slope middle and slope toe, respectively;the average content of AN had the trend of slope toe ＞ slope top ＞ slope middle, which were 54.37mg/kg, 34.53mg/kg and 26.60mg/kg, respectively; The average contents of AP and AK at the at the slope top, slope middle and slope toe were 3.52mg/kg, 2.52mg/kg and 2.15mg/kg and 36.67mg/kg, 36.67mg/kg and 38.33mg/kg, respectively; (3) The soil fertility index (SFI) in 0~20cm soil layer along different slope positions was 0.28~0.52, which had the trend of slope toe ＞ slope top ＞ slope middle.