铵态氮在非正规垃圾填埋场土壤中的赋存特征

应用连续分级提取法，对重庆市某非正规垃圾填埋场污染土壤中铵态氮的赋存形态进行分级测定，研究了各形态铵的赋存特征及影响因素。结果表明：土壤总铵量在116.32 ~ 241.66 mg·kg-1之间，平均值为（164.13±24.98） mg·kg-1，水溶态铵、可交换态铵和固定态铵的平均含量分别为（10.93±3.64）、（7.08±3.46）、（146.12±24.11） mg·kg-1；3种形态铵占总铵的比重大小为固定态铵 > 水溶态铵 > 可交换态铵。受雨水冲刷及淋滤影响，铵态氮有在下游点位积累的趋势。水溶态铵含量与有机碳含量、氧化还原电位呈极显著相关，与pH、粉粒含量及粘粒含量显著相关。可交换态铵与土壤氧化还原电位在垂直剖面上变化趋势一致，并与土壤粘粒含量呈极显著的负相关。固定态铵含量与土壤中粘粒含量呈极显著的正相关，与砂粒含量呈显著的负相关。

Characteristics of ammonium forms in soils at informal landfill

The contents of different forms of ammonium in the polluted soils at an informal landfill in Chongqing were measured by using the sequential extract methods, to study on the characteristics of ammonium occurrence and its influencing factors. The results indicated that total ammnium content ranged between 116.32 and 241.66 mg·kg-1, and the average content was 164.13 mg·kg-1. The contents of soluble ammonium, anchangeable ammonium and fixed ammonium are (10.93±3.64), (7.08±3.46) and (146.12±24.11) mg·kg-1 respectively. Ammonium forms ranged in the order of fixed ammonium > soluble ammonium > exchangeable ammonium. Influenced by the rainwater leaching, there was a tendency that ammonium accumulated downstream. There were highly significant positive correlations between contents of soluble ammonium and OC、ORP, significant correlation between contents of soluble ammonium and pH、silt content、clay content. The trends of exchangeable ammonium and soil ORP were consistent in the vertical section. There was highly significant negative correlation between exchangeble ammonium and clay content. There was highly significant positive correlation between fixed ammonium and clay content, significant negative correlation between fixed ammonium and sand content.