加拿大最佳管理措施流域评价项目评述

可持续农业的目的是在保持良好环境质量的同时获得较高的农业生产率。最佳管理措施(BMPs)在世界范围内已得到广泛应用,以减少农业污染物对水环境的影响。自2004年以来,加拿大农业部实施了最佳管理措施流域评价(WEBs)项目,在全国各地选择了有代表性的9个小流域,对BMPs的环境和经济效益进行评价。笔者对过去几年来WEBs项目的进展、研究方法及主要成果进行简要的回顾,并对在中国开展类似项目的必要性和启示进行了探讨。

A Review of the Canadian Watershed Evaluation of Beneficial Management Practices Project

The objective of sustainable agriculture is to maintain high agriculture productivity while preserving a sound environmental quality.However,water quality degradation caused by excessive sediment and nutrient runoff has become a critical environment impact on agricultural watersheds all over the world.Beneficial management practices(BMPs) are therefore designed and implemented to minimize these negative impacts on water environment.In 2004,Agriculture and Agri-Food Canada(AAFC) launched a watershed evaluation of BMPs(WEBs) project with a primary goal of assessing the environmental and economic performance of nine selected small watersheds across Canada under BMPs.The WEBs is composed of four main components,including biophysical evaluation,economic evaluation,hydrologic modeling,and integrated modeling.So far,WEBs has made significant progress in understanding the environmental and economic performance of the BMPs selected for the study and in validating hydrologic models using results from the field-tested BMPs,and WEBs has successfully begun to integrate biophysical and economic findings for planning for broader scales of land.The innovative and interdisciplinary research conducted in the WEBs watersheds will help farmers decide what practices might work best on their farm and will help the governments develop policies and programs to assist farmers in implementing effective BMPs for improving water quality and agri-environment.Additionally,the WEBs project has created the infrastructure,data sets and partnerships needed to continue a long-term watershed research,strengthen the initial findings and clarify the benefits of BMPs under different conditions.A general review of the progress,methods,and major findings of the WEBs project over the past years has been presented,and the necessity for China to implement similar projects has been discussed.