水文过程中灌区农田非点源氮的归趋研究进展

Review of the trends in the study of non-point source nitrogen in hydrological processes on farmland over irrigation district

天然降雨径流是灌区农田非点源氮污染形成的主要动力因素,研究降雨径流中农田氮素的流失规律及模拟方法对中国灌区非点源氮的综合治理具有重要意义。从农田氮素流失机理、影响因素以及预测方法等几个方面概述了水文过程中灌区农田非点源氮素归趋的研究进展,其中着重分析了水文过程中农田氮素流失预测的"黑箱"法、"解剖"法的优缺点和适用范围;并在此基础上,提出了中国开展灌区农田非点源氮污染研究的重点,包括典型研究单元选择、尺度界定以及不同水文路径中农田氮素流失的耦合模拟等。

The major driving force for non-point source nutrient losses from irrigated farmland comes from the natural rainfall-runoff process in the watershed. Study of the regularity in nutrient losses and the relevant modeling methodologies is thus important for the comprehensive pollution control of non-point source nitrogen in China's irrigation districts. This paper reviews the trends and progresses in the study of non-point source nitrogen in hydrological processes on farmlands, with emphasis on the aspects of the mechanism of nutrient losses and the influence factors, as well as the prediction methods. The scope and application of both black-box model and mechanism-dissection model are analyzed in detail. The advantage and disadvantage of the two models are also underlined. Based on the study, a priority list of promising research areas on the subject is proposed, including the selection of representative research units, the scale issues, and the coupling of farmland nutrient losses from different hydrologic flow pathways.