农业面源氮污染控制措施滞后效应形成机理与评估方法研究进展

推广实施最佳管理措施(BMPs)被认为是防治农业面源污染的有效途径，然而许多流域实施BMPs后通常难以在预测的时间内实现水质改善目标，导致人们对BMPs的有效性提出质疑。受流域内养分遗留效应影响，BMPs实施后的环境质量改善效益可能不会立刻显现(也即“滞后期”),这是由于过去人为活动输入的过量营养物质在流域水文传输和生物地球化学转化过程中的积累所致，当来自外部的污染负荷减少时，这部分营养物质的汇集和释放可能掩盖治理措施对于水质改善的影响。鉴于遗留的营养物质在延迟水质改善方面的关键作用，滞后期的量化评估对于全面分析污染成因，科学配置BMPs,有效治理流域农业面源污染，提升水质改善效率非常重要。以农业面源氮控制措施的滞后效应形成机理和评估方法为主线，概述了流域尺度氮累积和滞后效应产生的主要机理，述评了氮污染滞后效应的量化评估方法，提出目前大多数流域模型尚不能很好的表述滞后效应以及缺乏解决水文和生物地球化学遗留效应的能力，并对未来BMPs优化配置研究提出建议：(1)摸清流域水文传输过程和生物地球化学转化过程对BMPs控氮效益滞后期的影响，分析污染负荷削减的时空响应规律；(2)构建包含土壤、浅...

A review on the mechanisms and assessing methods for time lags in the responses of nitrogen loss to Best Management Practices

The implementation of Best Management Practices (BMPs) is considered to be an effective way to agricultural diffuse pollution control. However,the implementation of BMPs in many watersheds often makes it difficult to achieve water quality improvement goals within a predicted time, which is predicted by watershed managers and experts, which has led many to question the efficacy of these BMPs. In many cases, this limited response has been due to nutrients legacy in the basin, the environmental quality improvement benefits after the implementation of BMPs may not be immediately apparent, which is caused by the accumulation of excess nutrients imported by past human activities in the process of hydrological transport and biogeochemical transformation in the basin. When the pollution load from the outside decreases, the collection and release of these nutrients legacy may cover up the impact of treatment measures on water quality improvement. In view of the key role of nutrients legacy in delaying water quality improvement, the quantitative evaluation of the time lags is very important for comprehensive analysis of pollution causes, scientific allocation of BMPs, effective management of agricultural diffuse pollution in the basin, and improvement of water quality. Based on the review of research at home and abroad, this paper focuses on the mechanisms and assessing methods for time lags of nitrogen to BMPs in the basin, firstly, the main mechanisms of nitrogen accumulation and time lags at watershed scale are summarized. Then, the quantitative assessment methods of time lags of nitrogen pollution are reviewed. It is pointed out that most watershed models can not describe the time lags well and lack the ability to solve the legacy effects of hydrology and biogeochemistry. Finally, we put forward suggestions for future research on the optimization allocation of BMPs: (1) To investigate the effects of hydrological transport and biogeochemical transformation processes on time lags of BMPs nitrogen control efficiency, and analyze the spatio-temporal response of pollution load reduction; (2) To construct a watershed-scale BMPs nitrogen control efficiency lag model that includes the combination of soil, shallow aquifer and groundwater dynamics, and analyze the time required for pollutant emission reduction and water quality target improvement under different management scenarios; (3) To establish BMPs optimization allocation scheme covering time lags, so as to seek to achieve the maximum treatment efficiency in a short period of time as well as the dual synergistic environmental and economic benefits of agricultural diffuse pollution control strategy, effectively improve the efficiency, and provide theoretical basis and data support for management measures and policy formulation.