Nutritional quality of spinach (Amaranthus hybridus L.) cultivated using black soldier fly (hermetia illucens) waste compost

AbstractThe spinach can be cultivated on urban farms using compost from black soldier fly (BSF) larvae and urban organic waste. The study examined (1) the existence of heavy metal pollutants in household and market waste, (2) the impact of BSF larvae waste compost on spinach growth and product quality, and (3) the ingestion of compost components in spinach plant tissue. The experiment used a complete randomised block design (RCBD) with five treatments, specifically: (1) soil media without compost or urea; (2) soil with BSF compost as household waste substrate without fertiliser; (3) soil with household waste substrate BSF compost fertilised with urea; (4) soil with BSF compost as fruit waste substrate without fertiliser; and (5) soil with BSF compost as fruit waste substrate with fertiliser. Spinach growth and product, nutrient content, and heavy metal absorption in spinach tissue were parameters. BSF larva waste compost with household or fruit waste as a substrate contains macro and micronutrients required by plants and heavy metals that may harm vegetable plant tissues. Applying BSF larvae waste compost increased the vitamin A, vitamin C, chlorophyll, and carotene content in spinach production. The spinach product showed no significant difference in fibre, nitrate, nitrite, and oxalate levels compared to the control (100% soil). While the plant did absorb heavy metals (Cu, Pb, Cd, Zn) from the compost, the concentrations were below the threshold set by WHO/FAO. The use of compost for organic vegetable cultivation ought to be appropriately evaluated due to the potential existence of heavy metals.