中文摘要：

针对灌区农业非点源污染难以监测控制的具体特点,基于单元分析的观点,提出了负荷贡献率的概念,并在此基础上,建立了灌区农业非点源污染负荷估算方法;以青铜峡灌区为例,利用2005—2006年灌溉周期灌排水质监测试验资料对灌区年农业非点源污染矿化度、铵氮、总氮和总磷负荷进行了估算,并与平均浓度法进行比较。计算结果表明：青铜峡灌区农业非点源污染年输出盐分283万t,铵氮0.55万t,总氮4.11万t,总磷123 t;结合黄河干流控制断面水质资料比较分析,青铜峡灌区农业非点源污染负荷中盐分输出占干流区间增量的70%,铵氮和总氮分别是区间点源污染负荷的0.28倍和1.52倍,对黄河干流水质影响很大;而总磷由于输出量较小,对干流水质影响不大。

英文摘要：

Aimed at the specific characteristics of agricultural non-point source pollution being difficult to monitor and control in irrigation areas, and based on the viewpoint of unit analysis, a concept of load contribution rate was put forward. On such a basis, a model was established for assessment of agricultural non-point source pollution load in irrigation areas. A case study of the Qingtongxia irrigation area was carried out making use of the quality monitoring data of irrigation and drainage waters in the irrigation year of 2005 - 2006. Annual mineralization degree and ammonia nitrogen, total nitrogen and total phosphorus loads of agricultural non-point source pollution were estimated by using the model. Comparison with the mean concentration method showed that the new method was more reasonable. The results show that the annual agricultural non-point source pollution in the Qingtongxia irrigation area outputted 283 × 10^4 t salt, 0.55 × 10^4t ammonia nitrogen, 4.11 × 10^4t total nitrogen, and 123 t total phosphorus. Compared against the water quality data of the control section of the Yellow River, the output of salt accounted for about 70% of the increment of salt in the mainstream of the river; and the load of ammonia nitrogen and total nitrogen was 0.28 and 1.52 times as much as the point source pollution load of the control section, which causes great impact on water quality of the trunk course of the Yellow River; however, the output of total P was quite limited and so was its impact.