乐山市动物类产品水足迹测算分析

Assessment of water footprint of animal products in Leshan City

产品水足迹能反映人类活动在产品全生命周期中对水资源的消耗情况,为水资源的合理分配和利用提供科学依据。以乐山市为例,运用水足迹的理论和方法,测算了动物从出生到出栏过程中的虚拟水量以及出栏后加工成肉类产品期间的生产用水量。结果显示:乐山市动物产品总水足迹在2000—2011年呈上升趋势,2011年较2000年总水足迹增加了22.23亿立方米。比较不同种类动物产品水足迹,由大到小为牛肉>羊肉>猪肉>其它禽肉>兔肉>水产品>禽蛋>奶类。从水足迹构成看,年虚拟水量占总水足迹的比重在56.03—60.70%之间。动物产品的耗水环节主要为饲料用水以及出栏后动物产品的加工过程,建议采取改善饲料成分、改变养殖模式以及加强虚拟水贸易等措施,从而有效降低动物产品的水足迹。

Water footprint assessment is to measure fresh water consumption during the full life cycle of a product,which provides insight into better policy making on water resources allocation.In order to identity the water intensive sector,this paper provides a holistic water footprint assessment for animal products by taking Leshan City as a case example.The water footprint of animal products is composed of the virtual water content of a live animal during its entire lifespan,and the water consumption while distributing various meat products from the animals,in which the virtual water contains the water use of feeding,drinking and servicing.Results show that the total water footprint of animal products reaches4.42billion cubic meters in the year of2011,being increased by2.23billion cubic meters compared with that in the year of2000.Compared with various categories of the water footprints,a sequence of the measured animal products is ranked from the highest to the lowest grade,i.e.beef is ranked as the most water intensive product,mutton the second,pork the third,poultry the fourth,rabbit meat the fifth,aquatic products the sixth,and dairy products the least.From the perspective of the constitution of the water footprint,the virtual water consumption accounts for the total water footprint between56.03%and60.70%.In addition,the most water consumed sectors are identified as the virtual water requirement of the feed ingredients during the entire lifespan of the live animal,and the manufacturing process of the corresponding animal products.It is further suggested adjusting the feed ingredients,increasing the feed conversion rate,and using the agricultural by-products,e.g.straw,wheat bran,husk etc.,to reduce the water consumption in the feed sector.For the sector of the manufacturing process of the animal products,it is recommended to minimize the associated water footprint by implementation of cleaner production.Through the enhancement of modernized breeding and the promotion of virtual water trade,the water efficiency is expected to be improved,thus to reduce the total water footprint.