应用Manure-DNDC模型模拟畜禽养殖氮素污染

畜禽养殖是重要的农业面源氮素污染源头,大量的畜禽粪便施入农田后,会加大农田氮素径流和淋溶损失强度。畜禽养殖废弃物氮素污染过程复杂,涉及到动物自身营养循环以及废弃物通过不同途径进入环境的过程,目前大多通过排放系数法估算畜禽养殖过程产生的氮素污染负荷。该文选用最新版Manure-DNDC模型,以山东小清河流域为例,模拟畜禽养殖及废弃物处理的生物地球化学过程,分析氮素在动物、畜禽粪便、农田之间的迁移转化,探讨该过程中氮素的主要损失途径以及污染物负荷的时空变化特征。模拟结果表明,小清河流域2008年畜禽养殖及粪便处理场所氮素径流损失4.66万t,粪便施入农田后的氮素径流和淋溶损失分别为0.1、0.51万t。

Modelling nitrogen pollution from livestock breeding using Manure-DNDC model

Livestock and poultry breeding is one of the most important sources for agricultural non-point source nitrogen pollution. After application of manure fertilizer, the intensity of nitrogen losses through soil erosion and leaching in arable land will increase dramatically. Livestock breeding and manure management is a complicate process including nutrient cycling in animal body and transportation of waste from manure to environment through different routes. Discharge coefficient method was widely used for the evaluation of nitrogen pollution loads from animal breeding. The newest Manure-DNDC model was used for the modelling of biogeochemistry process in animal breeding and manure management, with a case study of Xiaoqinghe watershed in Shandong province. Nitrogen transportation and transfer in animal body, manure and agricultural land, main ways of nitrogen losses as well as spatial and temporal distribution of pollution were analyzed in the paper. The results indicated that nitrogen loss in the process of animal breeding and manure fertilizer application was 46.6 million kg N in Xiaoqinghe watershed in 2008. Nitrogen losses from soil erosion and leaching in arable land caused by manure application were 1 million kg and 5.1 million kg, respectively.