The Effect of Different Ratio Coensiling Sweet Sorghum and Soybean on Microbial Community, Fermentation, Chemical, and In Vitro Gas Characteristics in Comparison with Maize

This study evaluates the effects of coensiling sweet sorghum and soybean at varying ratios on microbial communities, fermentation quality, chemical composition, and in vitro gas production, using maize silage as a control. Sweet sorghum and soybean were combined in five ratios: 100% sweet sorghum, 75% sweet sorghum + 25% soybean, 50% sweet sorghum + 50% soybean, 25% sweet sorghum + 75% soybean, and 100% soybean. Results demonstrated that the 75% sweet sorghum + 25% soybean ratio produced the highest total biomass yield among the intercropping systems. After ensiling, pure silage of sweet sorghum and soybean had the highest value for dry matter (DM) yield and crude protein (CP) content, respectively. Among the mixed silages, 50% sweet sorghum + 50% soybean showed the highest Lactobacillus abundance, and 75% sweet sorghum + 25% soybean achieved a pH below 4. The highest in vitro total gas and methane production was observed in pure maize silage (as a control) with values of 55.32 and 10.82 ml/0.2 g DM, respectively. In the study, the best results were obtained with a mixture of 75% sweet sorghum + 25% soybean and 50% sweet sorghum + 50% soybean. This ratio optimized silage quality by providing high dry matter yield, low pH, and balanced fermentation profile. These findings suggest that sweet sorghum–soybean mixtures are a promising alternative to maize silage for improving feed quality and environmental sustainability.