A microbial-based composition provides a co-cultured microorganism consortium in culture medium that includes one or more Acetobacter sp., Bacillus sp., Bifidobacterium sp., Enter ococus sp., Gluconacetobacter sp., Lactobacillus sp., Rhodopseudomonas sp., Saccharomyces sp., Pichia sp., and Trichoderma sp., as well as a carbon source and chlorine-free water. In some embodiments, the microbial-based composition is useful in the agricultural industry as a plant growth promoting and silage-enhancing agent. For plant growth promotion applications, the microbial-based composition may be applied to the foliar surface of a plant or to the plant growth medium, such as soil or hydroponic solution, surrounding the plant. In silage operations, the microbial-based composition may be applied to a cut plant product during one or more stages in the silage process.