Regulation of soil enzyme activity and bacterial communities by food waste compost application during field tobacco cultivation cycle

Food waste (FW) composting is an effective waste resource utilization method; however, only limited approaches of FW compost application in agriculture have been investigated. This study reports changes in soil chemical properties, enzyme activities, and bacterial communities at different tillage stages and its effects on tobacco biomass after FW compost application in tobacco cultivation field experiments. The results showed that FW compost increased tobacco biomass. Also, FW compost functioned as a fertilizer that acted mainly during the maturity (September) and fallow (December) periods of tobacco, and its effect was enhanced with increasing application rates. FW compost significantly increased soil pH, organic carbon, total nitrogen, total phosphorus, alkaliolytic nitrogen, and available phosphorus content. It enhanced soil urease, acid phosphatase, fluorescein diacetate hydrolase, and polyphenol oxidase activities. FW compost application increased soil bacterial diversity, increasing the relative abundance of dominant bacteria such as Proteobacteria and Bacteroidetes while decreasing the relative abundance of Acidobacteria and Chloroflexi. Bacterial chemoheterotrophy, aerobic_chemoheterotrophy, ureolysis, chloroplasts, nitrogen_fixation, and fermentation functions were enhanced, and the complexity of ecological networks among bacterial species increased. A combined ranking analysis showed that the soil's available phosphorus, pH, alkaline nitrogen, and total phosphorus content were the main factors influencing bacterial population dynamics. In conclusion, FW composts can be used as an alternative to fertilizers. They exerts their beneficial properties by regulating bacterial communities mainly through soil chemistry, indirectly enhancing soil enzyme activity, and increasing tobacco yield.