论文部分内容阅读
GLEAMS是美国农业部开发的一个模拟农田氮磷循环的模型,主要用来评价农田管理措施的环境效益。本研究运用GLEAMS模型模拟了南京市东郊蔬菜生态系统的氮素循环,将氮素的主要来源和去向作了系统的分类和量化。模拟结果表明,从2003年7月到2005年7月,该区蔬菜生态系统通过施肥施入氮素3750kghm-2,降水与灌溉水引入氮素57.0kghm-2;氮素的输出主要有:淋溶1100kghm-2、流失43.0kghm-2、作物吸收960kghm-2、氨态氮挥发260kghm-2和反硝化913kghm-2,氮素盈余531kghm-2;并且计算出该区作物对氮素的吸收利用率仅为21.6%~25.2%。研究表明,该区农业生产对地下水环境的污染较大,农业生产系统的肥料利用率较低。本模拟研究为探索农田最佳施肥量,以及如何改善生态环境奠定了基础。
GLEAMS is a model developed by the U.S. Department of Agriculture to simulate the cycle of nitrogen and phosphorus in farmland and is mainly used to evaluate the environmental benefits of farmland management measures. In this study, the GLEAMS model was used to simulate the nitrogen cycle of the vegetable ecosystem in the eastern suburbs of Nanjing. The main sources and directions of nitrogen were systematically classified and quantified. The simulation results show that from July 2003 to July 2005, the vegetable ecosystem in the district applied 3750 kghm-2 of nitrogen through fertilization and introduced 57.0 kghm-2 of nitrogen into precipitation and irrigation water. The output of nitrogen mainly includes: The nitrogen uptake was up to 1100 kghm-2 and 43.0 kghm-2, respectively. The crop uptake was 960 kghm-2, ammonia nitrogen was 260 kghm-2 and denitrification was 913 kghm-2, and nitrogen surplus was 531 kghm-2. The rate is only 21.6% ~ 25.2%. The research shows that the agricultural production in this area has a great pollution to the groundwater environment and has a low fertilizer utilization rate in the agricultural production system. This simulation study laid the foundation for exploring the optimal fertilization rate of farmland and how to improve the ecological environment.