肥液浓度对膜孔单向交汇入渗NO3^--N运移特性的影响

Influence of fertilizer solution concentration on NO_3^--N transport characteristics under single-line interference film hole infiltration

通过室内入渗试验,研究了不同浓度的膜孔肥液单向交汇入渗NO3--N的分布特性。研究表明,不同肥液浓度的膜孔入渗湿润体膜孔中心和交汇界面中心垂向土壤NO3--N的浓度锋运移距离与土壤水分运动的湿润锋一致;肥液浓度越大,相同入渗时间的NO3--N浓度锋运移距离越大,土壤NO3--N浓度最大值越大,相同深度处土壤NO3--N浓度也越大。建立了肥液交汇入渗湿润体膜孔中心和交汇界面中心垂向土壤NO3--N浓度分布特征与湿润体深度之间的分段函数模型,经实测资料验证表明,该模型精度较高。入渗供水过程中,NO3--N浓度锋运移距离和浓度最大值随时间的延长而增大;再分布过程中,NO3--N浓度前锋运移距离随时间延长而增大,而NO3--N浓度最大值逐渐减小。

Based on lab experiment,NO3^--N concentration distribution characteristics under single-line interference film hole infiltration with different fertilizer solution concentration were studied.The concentration front transport distance of NO3^--N under single-line interference film hole infiltration had the same pattern as the movement of soil wetting front.The concentration front transport distance of NO3^--N and the maximum value of NO3^--N concentration in soil profile increased with the increase of the solution concentration in the same time.The NO3^--N concentration increased with the increase of the solution concentration at the same depth.The subsection function model for NO3^--N concentration distribution characteristics and wetting body depth of film hole center and interference interface center under fertilizer solution infiltration was developed,and the model was verified by measured data.The concentration front transport distance of NO3^-N and the maximum value of NO3^--N concentration increased with the increase of the time in the process of water supply.The concentration front transport distance of NO3^--N increased with the increase of the time in the process of redistribution but the maximum value of NO3^--N concentration decreased.