中文摘要：

为了评价灌区农田非点源磷素的流失风险,对内蒙古河套灌区典型作物地块中不同土层深度的土壤对磷素的吸附能力进行了测定,借助SPSS软件对试验结果进行统计分析,评价土壤磷素向水体的流失潜能以及可能的影响因素。结果表明：研究区不同地块的各层土壤均可以用Langmiur和Freundich方程来表征土壤对磷素的吸附特征,且Langmiur方程的拟合性要好于Freundich方程;小麦地块的各层吸附能力都较强,套种地块的吸附能力在试验中表现较差;表层土壤在不同地块的吸附能力差别不大,这可能与当地的复种习惯有关;表层土壤相对于深层土壤的流失潜能较高,即土壤中的磷素随农田退水的流失风险相对较大,但套种地块中磷素随渗漏淋失的潜能比对地表径流流失的潜能大;除Qm和EPC0之外,PSI值可以直接作为评价磷流失潜能的有效指标;磷素在农田地块的流失是河套灌区不可忽视的农业管理问题。该文为河套灌区科学合理施肥和非点源污染的防治提供了科学依据。

英文摘要：

To assess the phosphorus loss under different crops cultivations in farmland,soil samplings were taken in four typical crop types’ fields in five layers of 0-100 cm.Based on the isothermal methane-adsorbing experiments,SPSS software was applied to analyze the results statistically.The phosphorus loss potential was evaluated and the influence factors were discussed in this paper.The results revealed that the sorption characteristics of all the soil samples in the study area could be described by Langmiur and Freundich equations,and the Langmiur equation fit better.The soil in wheat field showed better sorption of phosphorus than that of other crops.The soil samples of intercropping field demonstrated poor sorption capacity.The phosphorus sorption of the top soil in the different crop fields showed few variations.Compared with the phosphorus sorption of the deeper layers,the top soil was prone to lose along with farmland drainage except in the intercropping field,where the phosphorus loss with seepage vertically into groundwater was the preferential way.Phosphorus sorption index （PSI） was another effective parameter to assess the phosphorus loss potential except for the theoretically maximum sorption capacity Qm and the equilibrium phosphorus concentration at zero sorption（EPC0）.The conclusions of this paper can provide scientific references for appropriate scheduling on efficient fertilization,irrigation,and non-point source pollution control.