中文摘要：

通过吸附实验，研究了杭嘉湖流域某源头沟渠中沉积物对氨氮和磷酸盐的吸附动力学及吸附等温线特征，以揭示氮、磷迁移转化机制。结果表明，沉积物对氨氮和磷酸盐的吸附是一个复合动力学过程，包括快速吸附和慢速吸附2个阶段，主要吸附过程发生在0～5h之内，吸速率在0～1h较大，氨氮最大吸附速率为160mg·kg^-1·h^-1，磷酸盐最大吸附速率为300mg·kg^-1·h^-1。实验浓度范围内（氨氮0-50mg·L^-1，磷酸盐0-20mg·L^-1）沟渠沉积物对氨氮和磷酸盐的吸附等温线均呈良好线性变化。沉积物中固定态氨氮含量为9．81mg·kg^-1，沉积物对磷的吸附-解吸平衡质量浓度为0．046mg·L^-1，与同流域内湖泊河流相比均较低。说明氮、磷在农田沟渠中的迁移转化较快，与河流湖泊相比，氮、磷并未大量累积在沉积物中。

英文摘要：

Agriculture non-point pollution is attracting increasing interests. Interests are focused on the excess nutrient such as nitrogen （N） and phosphorus （P）which can lead to eutrophication. As the main connecting part between fields and lake or river, agricultural ditch system plays an important role in the retention of N and P. During the transportation and transformation in ditch system, N and P can be held up by some ways such as adsorption, nitrification, denitrification and emergent uptake. Adsorption is one of the important retention factors. Static adsorption experiments were performed to investigate the adsorption kinetic and isotherm characteristics of ammonia nitrogen and phosphate on ditch sediments. The results help to explain the mechanism of transportation and transformation of N and P as to control the loss N and P. The results showed that the adsorption included two phases：fast and slow adsorption. The adsorption on sediment mainly occurred within 0-5 h and the maximum adsorption rates of ammonia nitrogen and phosphate on ditch sediment were 160 mg·kg^-1·h^-1 and 300 mg·kg^-1·h^-1 respectively. The adsorption isotherms of ammonia nitrogen and phosphate fitted well with linear relation. The content of immobile ammonium in the sediment was 9.81 mg·kg^-1. The adsorption-resorption equilibrium concentration of phosphate was 0.046 mg·L^-1. According to above results, N and P did not accumulate much in ditches as that in other waters.