Effect of Chemical and Microbial Additives on Fermentation Profile, Chemical Composition, and Microbial Populations of Whole-Plant Soybean Silage

This study evaluated the effects of two chemical additives or a microbial inoculant on chemical composition and DM losses in whole-plant soybean silage. One-hundred and twenty mini-silos were used in a completely randomized design experiment with the following treatments: water without chloride (control, CON); a microbial inoculant (INO); a chemical additive containing 35–45% formic acid (FA type); and another chemical additive containing 50–60% propionic acid (PA type). Data were analyzed using mixed models of SAS, and treatment differences were evaluated by the following orthogonal contrasts: C1 = CON vs. additives (INO + FA type + PA type); C2 = INO vs. chemical additives (FA type + PA type); and C3 = PA type vs. FA type. Silage pH and ammonia nitrogen concentration were decreased, and concentrations of lactic acid and acetic acid were increased with additives. Counts of lactic acid bacteria were higher in silages with INO than with chemical additives. DM recovery increased with FA type and PA type. Additives increased DM and CP concentrations. Silage A-fraction proportion was greater with additives. Additives, particularly FA type and PA type, improved chemical composition and fermentative profile and reduced undigestible proportions of protein in whole-plant soybean silage. Chemical additives were more effective in reducing silage DM losses than INO.