Frass fertilizer application enhances agronomic and economic performance of Chinese cabbage intercropped with desmodium under vertical farming system.

Low soil fertility, coupled with reduced land for cultivation, has favoured vertical farming as an alternative to traditional agriculture among urban dwellers. This study focused on the effects of frass fertilizer application on yield, pest suppression, and economic performance of growing Chinese cabbage intercropped with Desmodium under multi-storey gardens. Treatments included NPK (10 kg/ha), liquid and powdered frass fertilizer, Desmodium intercrop, their combinations, and an unamended control. Liquid frass fertilizer produced 1.6-fold and 1.4-fold higher yield (27.40 ± 0.07 kg/garden), significantly outperforming the control and NPK, respectively. Plots treated with powdered frass fertilizer and Desmodium had increased yield with significantly reduced pest incidences and damage score. Crude protein [15-20%] and ash content of vegetables from plots treated with different frass fertilizer types, Desmodium and their combinations was significantly increased than those from plots with NPK or control [8-13%]. Vegetable yield from plots treated with liquid frass fertilizer, translated to higher net profit margin with 75.14% return on investment. These findings demonstrated that the integration of frass fertilizer into multi-storey gardening in urban areas would open new ways of enhancing sustainable and safe food production which is the cornerstone of addressing food insecurity given the growing challenges of climate change and population growth.