Abstract: This study conducted in Nyingchi, Tibet, explored the effect on silage fermentation quality and microbial diversity of adding whole maize in in various proportions to whole buckwheat, when making silage. The combinations tested were: (A) whole buckwheat alone; (B) buckwheat:maize mixed at a 4:1 ratio; (C) buckwheat:maize mixed at a 3:2 ratio; (D) buckwheat:maize mixed at a 2:3 ratio; (E) buckwheat:maize mixed at a 1:4 ratio. On the 7th, 14th, 30th and 60th day after ensiling, samples were collected to determine the fermentation quality and microflora structure of silage. Compared with buckwheat alone (silage A) adding maize reduced the pH value and increased the lactic acid content of the silage. Both the ammonia nitrogen:total nitrogen values and the butyric acid content of the mixed silages met the requirements to be considered high quality silage. Maize addition also changed the microflora structure of the silage. Compared with silage A, maize addition increased the abundance of Firmicutes and lactic acid bacterial strains, and effectively inhibited the growth of spoilage bacteria, and this effect was more significant as the proportion of maize increased in silages B to E. Considering the desirability of maximization utilization of buckwheat which is suited to the local climate, and silage fermentation quality, we conclude that silage D with a 2:3 buckwheat:maize ratio would be the preferred formulation.

Key words: whole buckwheat, whole maize, mixed silage, fermentation quality, microbial diversity