Provided herein are microbial inoculants for use in increasing plant growth, plant productivity and/or soil quality, comprising strains of one or more bacterial species selected from Lactobacillus parafarraginis, Lactobacillus buchneri, Lactobacillus rapi and Lactobacillus zeae. Optionally the microbial inoculants also comprise a strain of Acetobacter fabarum and/or a strain of Candida ethanolica. Also provided are fertilizer compositions comprising said microbial inoculants.