Abrahão Raphael, Carvalho Monica, Causapé Jesús
Federal University of Paraíba (UFPB), Cidade Universitária, João Pessoa, Paraíba, 58051-900, Brazil.
Geological Survey of Spain (IGME), C/ Manuel Lasala 44, 9°B, 50006, Zaragoza, Spain.
Environ Sci Pollut Res Int. 2017 Feb;24(6):5647-5653. doi: 10.1007/s11356-016-8322-5. Epub 2016 Dec 30.
Irrigation increases yields and allows several crops to be produced in regions where it would be naturally impossible due to limited rainfall. However, irrigation can cause several negative environmental impacts, and it is important to understand these in depth for the correct application of mitigation measures. The life cycle assessment methodology was applied herein to compare the main irrigated and non-irrigated crops in Northeast Spain (corn and wheat, respectively), identifying those processes with greater contribution to environmental impacts (carbon and water footprint categories) and providing scientifically-sound information to facilitate government decisions. Due to concerns about climate change and water availability, the methods selected for evaluation of environmental impacts were IPCC 2013 GWP (carbon footprint) and water scarcity indicator (water footprint). The area studied, a 7.38-km basin, was monitored for 12 years, including the period before, during, and after the implementation of irrigation. The functional unit, to which all material and energy flows were associated with, was the cultivation of 1 ha, throughout 1 year. The overall carbon footprint for irrigated corn was higher, but when considering the higher productivity achieved with irrigation, the emissions per kilogram of corn decrease and finally favor this irrigated crop. When considering the water footprint, the volumes of irrigation water applied were so high that productivity could not compensate for the negative impacts associated with water use in the case of corn. Nevertheless, consideration of productivities and gross incomes brings the results closer. Fertilizer use (carbon footprint) and irrigation water (water footprint) were the main contributors to the negative impacts detected.
灌溉提高了产量，并使一些作物能够在因降雨有限而自然无法种植的地区生长。然而，灌溉可能会对环境造成一些负面影响，深入了解这些影响对于正确应用缓解措施至关重要。本文应用生命周期评估方法，比较了西班牙东北部主要的灌溉作物和非灌溉作物（分别为玉米和小麦），确定了对环境影响（碳足迹和水足迹类别）贡献较大的那些过程，并提供科学合理的信息以促进政府决策。由于对气候变化和水资源可用性的担忧，选择用于评估环境影响的方法是IPCC 2013全球升温潜能值（碳足迹）和缺水指标（水足迹）。所研究的区域是一个7.38平方公里的流域，监测了12年，包括灌溉实施前、实施期间和实施后的时期。所有物质和能量流与之相关联的功能单位是全年种植1公顷土地。灌溉玉米的总体碳足迹较高，但考虑到灌溉所实现的更高生产力，每公斤玉米的排放量会降低，最终有利于这种灌溉作物。在考虑水足迹时，灌溉用水量如此之高，以至于在玉米种植中生产力无法弥补与用水相关的负面影响。然而，考虑到生产力和总收入，结果会更接近。肥料使用（碳足迹）和灌溉用水（水足迹）是所检测到的负面影响的主要贡献因素。
