西辽河流域沙土对磷的吸附行为

采用小型回填式土柱动态吸附试验研究了西辽河流域沙土对磷的吸附行为. 结果表明:沙土对磷的吸附行为符合Freundlich吸附方程和Langmuir吸附方程，且前者更优. 吸附分配系数(k)平均值为31.55，磷饱和吸附量平均值为312.55 mg/kg. 沙土对磷的吸附方式以物理吸附为主，易淋失，仍存在一定的环境风险. 固定沙土中的微团聚体因存在以孔隙填充方式的磷吸附，所以其对磷的吸附能力最强，磷淋失的环境风险最小；而流动沙土对磷的吸附能力最弱，磷淋失的环境风险最大. 农田和林地沙土对磷的吸附能力最强，磷淋失的环境风险最小，是沙土的最佳利用方式. 沙土对磷的吸附分配系数及饱和吸附量与土壤w(粗黏粒)，w(黏粒)和w(有机质)呈极显著正相关. 

Sorption Behavior of Phosphorus on Sandy Soil in Western Liao River Basin

Sorption behavior of phosphorus on sandy soil in the Western Liao River basin was studied by dynamic sorption experimentation in a small backfilled earth-pillar.The results indicate that the behavior of phosphorus sorption conforms to the Freundlich and Langmuir isotherms.Further results show that the Freundlich has an advantage over the Langmuir isotherm,the average partition coefficient is 31.55,and the average phosphorus-saturated sorption is 312.55 mg /kg.The modes of phosphorus sorption are based on physical sorption,which is easy to leach out of the environment.Therefore,there is still a certain risk to the environment.The micro-aggregates of fixed sandy soil have a sorption mode with pore filling.As a result,fixed sandy soil or forest and farmland sandy soil has the strongest sorption capacity,and the environmental risk is at a minimum.Therefore,forestry or agriculture is the best use mode of sandy soil.Mobile sandy soil has a weak sorption capacity,and its environmental risk is at a maximum.The conclusion indicates that there is an obvious,positive correlation between phosphorus-saturated sorption or partition coefficient and coarse clay or clay content.In addition,phosphorus-saturated sorption and partition coefficient show highly obvious positive correlations to the organic matter content of sandy soil.