Effect Of Microbial Additives On The Mixed-silage Quality For Corn Stover And Cabbage Waste And Bacterial Diversity

Corn stover is one of the main crops in the central and northern C hina, while the structural contradiction that the immediately utilization of corn stover is far less than the total amount of its harvest is caused by seasonal harvest stover characteristics which leads to spoilage and uneasily effective long-term preservation of the raw materials. Therefore, it is necessary to find a long-term storage method. Silage is a good way to save the crop stover with seasonal storage. Due to the rural farming conditions and habits, most of the dry and yellow raw materials are harvested in stover wilting resulting in huge loss of water, sugar, woody fibrosis and even height that can not directly be applied to silage. Furthermore, many abandoned waste vegetables(tail dish) are leading to environment pollution for rural or city with the increasing flow of vegetables and the development of commercial vegetable acreage and consumption.In this paper, dry corn stovers and waste cabbage were selected as raw materials with an optimal mixture ratio of 71%. The experimental was designed 5 sub-groups:The corn stover single silage group SE, the additive- free group of corn stovers and waste cabbage mixed silage ME, the group of Lactobacillus plantarum(LP)、Lactobacillus buchneri(LB)and Pichia anomala(PA)were selected as microbial additives. After storing for 170 days at room temperature and protected from light, the corn stover quality and bacterial communities was analyzed in the sense of sensory evaluation group, chemical composition, fermentation quality and bacterial diversity at regular intervals(30 days or 40 days). The main findings are displayed as follows:(1) Compared with the sensory evaluation in each group, each group did not appeared putrefaction in fermentation period can continue to extend the mixed silage fermentation period. And the group of LP, LB and PA was better than SE and ME group. Furthermore, effects on the sensory of the group of LP and LB were slightly better than PA group while the results of LB group in fermentation at 170 d showed better sensory evaluation and was still the master, other group reduced to average.(2) According to a comprehensive analysis of the chemical composition of each group, the better mixed silage group was obtained by LP group. Its dry matter and dry matter recovery was significantly higher than other groups with the highest holocellulose stored 130 ~ 170 d. Dry matter of ME group was significantly lower than other groups.(3) The fermentation quality results of each group demonstrated that the quality fermented by SE group was poor due to the higher pH at 5.8 or more which can not meet the basic requirements of good silage(p H<4.5). The p H and lactic acid content of PA group were relatively better than other experimental groups while the butyric acid content at 130 d of the fermentation was also significantly higher than other groups. The ammonia nitrogen to total nitrogen of LP group were lower than other groups while the concentrations of acetic acid, ethanol and propionic acid were higher. The V-Score results of the additive corn stover group were significantly better than the group of SE and ME. It was unable to make accurate judgments of the optimal test groups from the fermentation quality perspective.(4) The bacterial diversity results showed that sequenced species diversity of the same amount, richness and OTU several communities on the genus level of LP group were lower than other groups indicating a relatively fewer concentrated species of the bacteria communities. From the door aspects, it can be seen that the Firmicutes level of bacteria communities during the fermentation period was alwa ys take in a dominant position. While LP group made the Lactobacillus the dominant lactic acid bacteria with a relatively higher abundance than other groups. It can be concluded as well from the clustering heatmap that similarity of bacterial community by the group of LB and PA was higher while the bacterial diversity between corn stover single silage group and other groups was quite different.The comprehensive results of mixed silage quality and bacterial diversity between corn stovers and waste cabbage showed that silage efficient in LP group was the better. However, although the results in line with the diversity characteristics of microbial silage of good raw material, some indicators of the quality of its mixed silage were still unable to satisfy the basic requirements of good silage, thus it needs deeply study on types optimization of additives to improve the silage quality of silage and lay foundation of stover realization of trans-seasonal storage.