The aim of this study was to investigate the diversity of dominant Clostridia community and screen targeted bacteriostatic lactic acid bacteria in high-moisture alfalfa silage through high-throughput sequencing combined with correlation network analyses. Sucrose group （sucrose added at 20 g·kg^-1 fresh matter， FM）， LAB group （LAB inoculant was composed of Lactiplantibacillus plantarum and Lentilactobacillus buchneri and applied at 10⁶ cfu·g^-1 FM） ， and control group were established. All groups were subjected to 56 days of anaerobic ensiling at ambient temperature. The results showed that severe butyric acid fermentation occurred in both the control and LAB groups. Compared to the control and LAB groups， the sucrose group significantly increased the lactic acid content （P<0.05）， while significantly decreased butyric acid， ammonia nitrogen， and Clostridia counts （P<0.05）. Clostridium sp. BTY5， Garciella sp. GK3， and Clostridiales bacterium mt11 were significantly positively correlated with butyric acid， ammonia nitrogen， and Clostridia counts （P<0.05）. L. buchneri and Lactobacillus melliventris were significantly negatively correlated with these three key Clostridia （P<0.05） and were significantly negatively correlated with pH， butyric acid， ammonia nitrogen， and Clostridia counts （P<0.05）. In conclusion， Clostridium sp. BTY5， Garciella sp. GK3， and Clostridiales bacterium mt11 were identified as the key Clostridia responsible for butyric acid fermentation in high-moisture alfalfa silage. The addition of sucrose can effectively improve silage fermentation quality. L. buchneri and L. melliventris have the potential to inhibit targeted key Clostridia.

Alfalfa silage  /  Clostridia  /  Lactic acid bacteria  /  Fermentation quality