Sostenipra Research Group (2017 SGR 1683), Institut de Ciència i Tecnologia Ambientals (CEX2019-000940-M), Z Building, Universitat Autònoma de Barcelona (UAB), Campus UAB, 08193 Bellaterra, Barcelona, Spain.
Sostenipra Research Group (2017 SGR 1683), Institut de Ciència i Tecnologia Ambientals (CEX2019-000940-M), Z Building, Universitat Autònoma de Barcelona (UAB), Campus UAB, 08193 Bellaterra, Barcelona, Spain; Department of Chemical, Biological and Environmental Engineering, Universitat Autònoma de Barcelona (UAB), Campus UAB, 08193 Bellaterra, Barcelona, Spain.
Sci Total Environ. 2021 May 20;770:144744. doi: 10.1016/j.scitotenv.2020.144744. Epub 2021 Jan 23.
Urban agriculture, while being a promising solution to increase food sovereignty in cities, can lead to an unprecedented discharge of nutrient and fertilizer-related emissions into the urban environment. Especially relevant are nitrogen (N) and phosphorus (P), due to their contribution to marine and freshwater eutrophication. Therefore, alternative methods of fertilization need to be put into practice to avoid such impacts to the surrounding environment. Struvite, has been studied as a potential slow releasing fertilizer due to its high P content, while the bacteria rhizobium has been used to fix N directly from the atmosphere. Legumes, like the common bean are N-demanding crops capable of symbiosis with the bacteria rhizobium and have previously shown positive responses to fertilization with struvite. This study aims to analyze the environmental performance of plant production in hydroponic systems combining rhizobium inoculation and struvite (2 g, 5 g, 10 g, 20 g) irrigated with a N and P deficient nutrient solution, using life cycle analysis (LCA). The nutrient content of in- and out-going irrigation was analyzed as well as in plants and beans. The functional unit for the LCA was 1 kg of fresh beans. The results obtained indicate a yield reduction of 60% to 50% in comparison to the control which was irrigated with a full nutrient solution. The impacts from operational stage are less in all impact categories, where most significant reductions up to 69% and 59% are seen in marine-eutrophication and global warming respectively. Although the infrastructure does not change between treatments, its impacts increase due to the lower yields. We determine that below a 10% of the control yield, the alternative systems have more impact than the use of conventional mineral fertilizers in almost all impact categories, thus pointing to the importance of infrastructure to truly reduce environmental impacts for urban agriculture.
城市农业虽然是增加城市粮食主权的有前途的解决方案，但会导致营养和肥料相关排放物以前所未有的速度排放到城市环境中。氮（N）和磷（P）尤为相关，因为它们会导致海洋和淡水中的富营养化。因此，需要采用替代施肥方法来避免对周围环境造成这种影响。鸟粪石由于其高磷含量而被研究为一种潜在的缓释肥料，而根瘤菌则被用于直接从大气中固定 N。豆类，如普通豆是对 N 有需求的作物，能够与根瘤菌共生，并且以前对用鸟粪石施肥表现出积极的响应。本研究旨在分析在水培系统中结合根瘤菌接种和鸟粪石（2 g、5 g、10 g、20 g）的植物生产的环境性能，这些系统用氮和磷缺乏的营养液灌溉，采用生命周期分析（LCA）。分析了进出灌溉的营养含量以及植物和豆类中的营养含量。LCA 的功能单位是 1 公斤新鲜豆类。结果表明，与用全营养溶液灌溉的对照相比，产量降低了 60%至 50%。在所有影响类别中，操作阶段的影响都较小，其中海洋富营养化和全球变暖的影响分别最大，减少了 69%和 59%。尽管处理之间的基础设施没有变化，但由于产量较低，其影响会增加。我们确定，在对照产量的 10%以下，替代系统在几乎所有影响类别中的影响都大于传统矿物肥料的使用，从而表明基础设施的重要性，以真正减少城市农业的环境影响。
