Effects of lactic acid bacteria and molasses additives on the microbial community and fermentation quality of soybean silage

•Soybean ensiled with lactic acid bacteria inoculant and molasses.•All additives improved fermentation quality of soybean silage.•Combined addition of lactic acid bacteria and molasses showed best silage quality.•Molasses enriched the abundance of Lactobacillus.•Combination of lactic acid bacteria and molasses decreased Clostridia abundance. The objective was to study effects of lactic acid bacteria (L) and molasses (M) on the microbial community and fermentation quality of soybean silage. Soybean was ensiled with no additive control (C), 0.5% molasses (0.5%M), 0.5%M+L (0.5%ML), 2%M, 2%M+L (2%ML) for 7, 14, 30 and 60days. The M-treated silages could increase the content of lactic acid and decrease butyric acid than control. Besides, higher crude protein was also observed in M-treated silages. With prolonged ensiling time, there was a reduction of the ratio of lactic acid/acetic acid in the 2%M-treated and 2%ML-treated silages. The combined addition of L and 2%M could enhance the account of desirable Lactobacillus and inhibit the growth of undesirable microorganism such as Clostridia and Enterobacter. In summary, the silage quality of soybean was improved with the addition of L and M.