中文摘要：

通过文献查阅和采样分析，建立华北农田小麦-玉米轮作体系下土壤重金属输入、输出数据库，分析不同重金属输入源所占比例；通过模型计算不同情景下土壤中不同重金属元素累积速率和累积速率的频率分布，分析土壤不同重金属的积累特征。结果表明，本轮作体系和条件下，Cu、Zn、Cd、Ni、Pb、Cr 6种重金属元素的主要输入源为畜禽粪便有机肥，其占总输入量的比例分别是：86.1%、83.8%、76.6%、72.5%、64.3%和46.3%；Hg、As的主要输入源为磷肥，其分别占总输入量的比例是52.6%和49.5%；大气沉降也是农田土壤中Hg的重要输入源之一。华北农田小麦-玉米轮作体系秸秆还田和地下水灌溉条件下土壤重金属元素累积速率的中位值分别为：Cd 0.00238 mg·kg^-1·a^-1，As 0.0298 mg·kg^-1·a^-1，Hg 0.00109 mg·kg^-1·a^-1，Pb 0.0507 mg·kg^-1·a^-1，Cr 0.0502 mg·kg^-1·a^-1， Cu 0.110 mg·kg^-1·a^-1，Zn 0.348 mg·kg^-1·a^-1，Ni 0.0393 mg·kg^-1·a^-1。根据我国土壤环境质量II级标准（GB 15618-1995），本体系和条件下土壤中Cd、Cr、Ni最易超标，在农田土壤重金属污染防治中应重点关注。

英文摘要：

Through literatures review and samplings analysis, the database of heavy metal in wheat-corn field system of north China was built and the percentage of different sourcees was analysed. The accumulation rate and frequency distribution of accumulation rate of heavy metals in different situations were counted by modeling, and accumulation characteristics of different elements were analysed. The result showed that the manure was the main source of Cu、Zn、Cd、Ni、Pb、Cr in wheat-corn field system of north China farmland, with the percentage of 86.1%、83.8%、76.6%、72.5%、64.3%and 46.3%, respectively;Phosphate fertilizer was the main source of Hg and As, the percentage of them were 52.6%and 49.5%, respectively;Besides, atmospheric deposition was also one of the main sources of Hg in the farmland soil. According to the accumulation rate frequency distribution, accumulation rate of each elements was Cd 0.002 38 mg·kg^-1·a^-1, As 0.029 8 mg·kg^-1·a^-1, Hg 0.001 09 mg·kg^-1·a^-1, Pb 0.050 7 mg·kg^-1·a^-1, Cr 0.050 2 mg·kg^-1·a^-1, Cu 0.110 mg·kg^-1·a^-1, Zn 0.348 mg·kg^-1·a^-1, Ni 0.039 3 mg·kg^-1·a^-1, respectively. According to the soil environmental quality secondary standards, Cd、Cr、Ni was most likely to exceed the standard, so these three elements should be caused more concern.