Effects of the addition of different additives and biological agents on the quality of potato stem and leaf silage in Shigatse

Fresh potato stems and leaves were used as raw material to produce silage in a laboratory-scale experiment in Shigatse. Formic acid, urea, salt, and six different types of biological agents (A, active lactic acid bacteria freeze-dried powder;B, YIJAYI straw fermentation agent; C, QIANMU EM bacteria seed; D, BAIYIBAO EM strain; E, WEITEMEI probiotic bacteria; F, degradation agent of coarse fodder) were used as ensiling additives. Corn flour, wheat bran, polymeric grass, alfalfa, forage maize straw, forage corn stalk, oat straw, barley straw, and rape shell were used to prepare mixed silage. Silage was vacuum-packed in polyethylene bags. On the basis of biochemical analysis and sensory evaluation, we adopted the subordinate function method to evaluate silage quality. The results obtained were as follows. Silage completed fermentation and after 30 days entered a stable stage, which can effectively maintain moisture and nutrients for a long time. The quality of silage produced with potato stems and leaves individually was poor, but could be improved by adding biological agents, i.e., formic acid, wheat bran, corn flour, forage maize straw, and oat grass. Among these, wheat bran was better than corn flour, and forage maize straw was better than oat grass. Although polymeric grass and alfalfa are nutritious, their high water contents result in poor fermentation when ensiled with potato stems and leaves. Rape shell is not suitable for mixed storage with potato stems and leaves. Among the biological agents assessed, the fermentation effects of A and B were better than those of E and F. The effects of the following three silage treatments are best: Potato stems and leaves+30% wheat bran, potato stems and leaves+0.3% urea+0.4% salt+30% wheat bran+D, and potato stems and leaves+30% wheat bran+B.