Fish Effluent as a Source of Water and Nutrients for Sustainable Urban Agriculture

Urban Farm DB summary

A study (2022, Agriculture) examined integrating urban agriculture with aquaculture to reduce water use and cost, competition for water, chemical fertilizer use, and the environmental impact of discharging nutrient-rich agricultural water into fresh and saltwater bodies, noting that urban aquaculture could also directly benefit human health as a local source of lean protein, while few studies had demonstrated the practical feasibility and production advantages of using aquaculture wastewater to fertigate specialty crops in cities. Four spring crops (bok choy, tatsoi, radish, turnip) and two fall crops (pole beans, sugar snap peas) were grown using nutrient-rich fish aquaculture effluent versus well or municipal water to evaluate effects on soil fertility and crop production. The fish effluent raised soil pH and potassium and increased pole bean count by 9.1% (bean mass trended toward significance but was not conclusive); the soils used were relatively nutrient-rich even before the effluent was applied, which may explain the limited impact, and the study suggests differences could be more pronounced in acidic, nutrient-poor soils or with longer-duration fertigation.