Circular urban agriculture: Food waste-derived fertilizers lead to comparable yields in a tomato greenhouse experiment

Urban agriculture could promote sustainable food systems by localizing food production and consumption and increasing climate resilience. This study investigated the use of liquid food waste-derived digestate (FWDD) as biofertilizer in community learning gardens. Tomato plants (Solanum lycopersicum L.) were grown in a greenhouse in either potting medium alone (1) or amended with synthetic mineral fertilizer (2), compost (3), or a compost-FWDD blend (4). The control amended with mineral fertilizer and the compost-FWDD blend exhibited similar plant height and aboveground biomass area. While the positive control produced the highest total fruit yield, the total edible fruit yield and total fruit weight were similar in the compost-FWDD blend, which yielded the largest average fruit weight. Compost and compost-FWDD treatments produced lighter, tarter, but not more acidic tomatoes. No detrimental soil effects of FWDD amendment were observed. FWDD may increase the circularity and social resilience of historically underserved urban communities, although further research is needed to assess social perceptions and to quantify the life cycle impacts of FWDD in this context.