Sostenipra Research Group (SGR 01412), Institute of Environmental Sciences and Technology (CEX2019-000940-M), Z Building, Universitat Autònoma de Barcelona (UAB), Campus UAB, 08193 Bellaterra, Barcelona, Spain.
Sostenipra Research Group (SGR 01412), Institute of Environmental Sciences and Technology (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 Dec 10;799:149424. doi: 10.1016/j.scitotenv.2021.149424. Epub 2021 Aug 3.
Urban agriculture (UA) is a means for cities to become more resilient in terms of food sovereignty while shortening the distance between production and consumption. However, intensive soilless UA still depends on the use of fertilizers, which relies on depleting non-renewable resources such as phosphorous (P) and causes both local and global impact for its production and application. With the aim to reduce such impacts and encourage a more efficient use of nutrients, this study assesses the feasibility of using struvite precipitated from an urban wastewater treatment plant as the unique source of P fertilizer. To do so, we apply various quantities of struvite (ranging from 1 to 20 g/plant) to the substrate of a hydroponic Phaseolus vulgaris crop and determine the yield, water flows and P balances. The results show that treatments with more than 5 g of struvite per plant produced a higher yield (maximum of 181.41 g/plant) than the control (134.6 g/plant) with mineral fertilizer (KPOH). On the other hand, P concentration in all plant organs was always lower when using struvite than when using chemical fertilizer. Finally, the fact that different amounts of struvite remained undissolved in all treatments denotes the importance to balance between a correct P supply to the plant and a decrease of P lost through the leachates, based on the amount of struvite and the irrigated water. The findings of this study show that it is feasible for UA to efficiently use locally recovered nutrients such as P to produce local food.
城市农业（UA）是城市在粮食主权方面变得更具弹性的一种手段，同时缩短了生产和消费之间的距离。然而，集约化无土 UA 仍然依赖于化肥的使用，而化肥的使用依赖于不可再生资源磷（P）的消耗，并对其生产和应用造成了当地和全球的影响。为了减少这种影响并鼓励更有效地利用养分，本研究评估了利用城市污水处理厂沉淀的鸟粪石作为唯一 P 肥料来源的可行性。为此，我们将各种数量的鸟粪石（1 至 20 克/株）应用于水培菜豆的基质中，并确定产量、水流和 P 平衡。结果表明，与使用矿物肥料（KPOH）的对照（134.6 克/株）相比，每株植物使用超过 5 克鸟粪石的处理产生了更高的产量（最高 181.41 克/株）。另一方面，当使用鸟粪石时，所有植物器官中的 P 浓度总是低于使用化学肥料时。最后，所有处理中都有不同数量的鸟粪石未溶解，这表明需要根据鸟粪石和灌溉水的数量，在向植物提供正确的 P 供应和减少通过淋溶损失的 P 之间取得平衡，这一点很重要。本研究的结果表明，UA 可以有效地利用本地回收的养分（如 P）来生产本地食品。
