Plant Growth Enhancement under Combined Amendments of Food Waste Digestate and Rhizosphere Microbial Co-Occurrence

Food waste contributes to environmental degradation by emitting greenhouse gases and depleting natural resources, but it also exacerbates global hunger and poverty. This study investigated the use of food waste digestate (FWD) as fertilizer on ornamental plant (Piper sarmentosum) cultivation under soil amendment growing media such as organic compost (OC), biochar, and rice husk (RH) in a 56-day trial. A significant increase in plant growth was observed in the potting mix with soil amendments combined with the application of FWD in comparison to the potting mix without the application. In comparison to soil amendments such as OC, FWD found a higher chlorophyll content index of 1.48%. In comparison to biochar, this was followed by 2.76% higher and 1.29% higher than RH. Furthermore, the number of leaves and leaf areas of plants increased significantly (>2%) with FWD added to soil amendments in comparison with OC and RH. The identified microbial phyla were Acidobacteriota, Actinobacteriota, Bacteroidota, Firmicutes, Proteobacteria, and Verrucomicrobiota, and some have closed to networking, like Firmicutes and Proteobacteria. Proteobacteria, Firmicutes, and Bacteroidetes were listed as plant growth-promoting microbe groups in the study. This approach promotes plant growth and offers a sustainable solution to recycling FW into fertilizer.