Effects of mixing ratio and additives on the quality of napier grass and whole-plant corn mixed silage

To provide a theoretical basis for the production of high-quality silage, this study investigated the effects of mixing ratio and additives on the quality of napier grass (Pennisetum purpureum) and whole-plant corn (Zea mays) mixed silage. Napier grass and whole-plant corn were used as raw materials and mixed in ratios of 10 ꞉ 0, 8 ꞉ 2, 6 ꞉ 4, 4 ꞉ 6, 2 ꞉ 8 and 0 ꞉ 10 by weight. Control and 0.01 g·kg⁻¹ compound microbial preparation treatments were designed for each mixed ratio. Nutritional composition and fermentation quality were analyzed after 40 days of fermentation. The results showed that silage quality was excellent in all treatments except for napier grass silage without additives. With increasing proportions of whole-plant corn, the dry matter, crude protein, and water-soluble carbohydrate contents tended to increase, while the acid detergent fiber content decreased significantly (P < 0.05). Lactic acid content also increased significantly (P < 0.05) with increase in whole-plant corn mixture ratios. The pH, ammonia nitrogen/total nitrogen, and acetic acid of the compound microbial preparation group were lower or significantly lower (P < 0.05) than those of the control group. Overall, the silage quality of napier grass can be improved by mixing whole-plant corn in a certain proportion and applying a compound microbial preparation. The silage effect of the 2 ꞉ 8 mixed ratio with compound microbial preparation was the best, closely followed by that of whole-plant corn treatment alone.