The Effects of Frass and Vermicompost Fertilization on the Biometrical Parameters of Plant and Soil Quality, and the Rhizobiome, in Red Beet (Beta vulgaris L.) Cultivation

Insect frass and vermicompost hold potential applications as fertilizers, with their abilities to improve plant resilience against unfavorable environmental conditions and increase their resistance to pests and diseases. In this study, we explored the effects of vermicompost fertilization, mealworm frass, and superworm frass as potential plant fertilizers for red beet cultivation. We analyzed the connections among chemical parameters, rhizobiome structure and function, and the biometrics of fertilizer-treated plants. In general, soils enriched with vermicompost and superworm frass exhibited the highest macroelement contents. Dry superworm frass fertilization was characterized by the increased availabilities of total nitrogen, NH4-N, and NO3-N. The use of vermicompost and mealworm frass resulted in significantly higher red beet biomass values. The presence of the highest N-fixation potential and key hormonal substances involved in plant development, such as auxins and gibberellins, was demonstrated using wet superworm frass. The results indicated that wet superworm frass, similar to vermicompost and dry superworm frass, exhibits high chemoheterotrophic potential. This suggests an r-type strategy and high adaptive flexibility of rhizobial bacteria. As a consequence, both life in the root zone and the microbiome itself may be better adapted to sudden, unfavorable environmental changes or attacks by plant pathogens.