农产品水足迹评价研究进展

水足迹是消费者或生产者直接或间接使用水资源量的衡量指标,并被广泛应用于全球或区域虚拟水贸易分析研究。本文从全球、国家或地区等不同空间尺度对农产品水足迹评价研究进行了比较全面的综述。近十几年来,农产品水足迹研究从2008年以前的全球农产品贸易虚拟水量分析评价为主,转向2009年以后国家或地区空间尺度的农产品形成过程中所消耗的直接和间接水量的详细核算研究为核心。水足迹评价具有明显的空间分布特征,为了获取准确、全面客观的农产品生产水足迹信息,必须要考虑区域地理特征、土壤理化特性、气候变化、生产技术及污染物生态毒性等因素的影响。水资源管理决策制定时应综合考虑农产品绿水、蓝水和灰水足迹,因为农产品的蓝水足迹表征了社会淡水资源的直接消耗,对国际市场贸易决策制定具有重要意义,而农产品灰水足迹评价则更明确地反映了农业生产对环境的影响程度。实现全球或区域农业水资源保护与可持续利用,不仅要提高农业生产水资源利用效率,还应该调整农业生产结构、农产品虚拟水贸易的模式和方向,减少农产品流通过程和饮食消费的水资源浪费。

A review of water footprint assessment for agricultural products

Water footprint (WF) is an indicator for both direct (domestic water use) and indirect (water required for industrial and agricultural production) water use of a consumer or producer.It has also been widely used in the analysis of global or regional virtual water trade.In the last decade,assessment of WF has been the focus of the footprint of rapid development.WF has three components (green,blue and grey water).This paper discussed a comprehensive review of the assessment of WF for agricultural products at different spatial scales,including global,regional and country scales.The main goal of the assessment of agricultural WF before 2008 was to determine global virtual water trade via agricultural products.However,the goal shifted to the rigorously quantification of three components for specific agricultural products and in specific geographical areas after 2009.As the assessment of WF has obvious spatial distribution characteristics,it was necessary to consider the influence of regional geographical characteristics,soil physical and chemical properties,climate change,as well as production technology and ecological toxicity of pollutants for building accurate,comprehensive and objective information on the WF of agricultural products.It was also necessary to take into account green water,blue water and gray water footprints for agricultural products in decision making on water resources management.This was because blue WF for agricultural products represented the direct consumption of freshwater resources,which was critical in decisions on international water trade market.The grey WF for agricultural products more clearly reflected the effect of agricultural production on the environment.In order to reach global or regional objectives on water resources conservation and sustainable utilization,not only the utilization efficiency of water resources in agricultural production needed improvement,but also the structure of agricultural production and both pattern and direction of virtual water trade for agricultural products needed adjustment.Furthermore,it was necessary to reduce waste of water resources in agricultural product cycle and food consumption.