Contribution of the bacterial community of poorly fermented oat silage to biogas emissions on the Qinghai Tibetan Plateau

To better utilize poorly fermented oat silage on the Qinghai Tibetan Plateau, 239 samples of this biomass were collected from the plateau temperate zone (PTZ), plateau subboreal zone (PSBZ), and nonplateau climatic zone (NPCZ) in the region and analyzed for microbial community, chemical composition and in vitro gas production. Climatic factors affect the bacterial α-diversity and β-diversity of poorly fermented oat silage, which led to the NPCZ having the highest relative abundance of Lactiplantibacillus plantarum. Furthermore, the gas production analysis showed that the NPCZ had the highest maximum cumulative gas emissions of methane. Through structural equation modeling analysis, environmental factors (solar radiation) affected methane emissions via the regulation of lactate production by L. plantarum. The enrichment of L. plantarum contributes to lactic acid production and thereby enhances methane emission from poorly fermented oat silage. Notably, there are many lactic acid bacteria detrimental to methane production in the PTZ. This knowledge will be helpful in revealing the mechanisms of environmental factors and microbial relationships influencing the metabolic processes of methane production, thereby providing a reference for the clean utilization of other poorly fermented silage.