Sasu-Boakye Y, Cederberg C, Wirsenius S
Department of Energy and Environment,Chalmers University of Technology,Gothenburg SE-412 96,Sweden.
Animal. 2014 Aug;8(8):1339-48. doi: 10.1017/S1751731114001293.
Livestock farmers in Sweden usually grow feed grains for livestock but import protein feed from outside Sweden. Aside from the economic implications, some environmental issues are associated with this practice. We used life cycle assessment to evaluate the impact of local protein feed production on land use and greenhouse gas emissions, compared with the use of imported protein feed, for pig meat and dairy milk produced in Sweden. Our results showed that local production reduced greenhouse gas emissions by 4.5% and 12%, respectively, for pigs and dairy cows. Land use for feed production in Sweden increased by 11% for pigs and 25% for dairy cows, but total land use decreased for pig production and increased for dairy milk production. Increased protein feed cultivation in Sweden decreased inputs needed for animal production and improved some ecological processes (e.g. nutrient recycling) of the farm systems. However, the differences in results between scenarios are relatively small and influenced to an extent by methodological choices such as co-product allocation. Moreover, it was difficult to assess the contribution of greenhouse emissions from land use change. The available accounting methods we applied did not adequately account for the potential land use changes and in some cases provided conflicting results. We conclude that local protein feed production presents an opportunity to reduce greenhouse gas emissions but at a cost of increasing land occupation in Sweden for feed production.
瑞典的家畜养殖户通常种植饲料谷物用于饲养家畜,但从瑞典境外进口蛋白质饲料。除了经济影响外,这种做法还带来了一些环境问题。我们运用生命周期评估法,评估了瑞典本地生产蛋白质饲料对土地利用和温室气体排放的影响,并与使用进口蛋白质饲料生产瑞典猪肉和牛奶的情况进行了比较。我们的结果表明,本地生产分别使猪和奶牛的温室气体排放量减少了4.5%和12%。瑞典用于饲料生产的土地,猪的增加了11%,奶牛的增加了25%,但猪肉生产的总土地利用减少,牛奶生产的总土地利用增加。瑞典蛋白质饲料种植的增加减少了动物生产所需的投入,并改善了农场系统的一些生态过程(如养分循环)。然而,不同情景之间的结果差异相对较小,并且在一定程度上受到诸如副产品分配等方法选择的影响。此外,很难评估土地利用变化产生的温室气体排放的贡献。我们应用的现有核算方法没有充分考虑潜在的土地利用变化,在某些情况下还给出了相互矛盾的结果。我们得出结论,本地生产蛋白质饲料提供了减少温室气体排放的机会,但代价是瑞典用于饲料生产的土地占用增加。