Abstract: The aim of this experiment was to investigate the effect of different moisture contents (67.69%，59.43%，47.26% and 38.07%) on the quality of alfalfa (Medicago sativa L.) silage after adding compound Lactobacillus and 2% molasses,respectively. The composite lactic acid bacteria were composed of Lactobacillus plantarum and Lactobacillus brucelli,with an equal addition of 1×10⁷ cfu·g^-1 FW. After anaerobic fermentation at room temperature,the nutritional quality,fermentation quality and microbial quantity of silage alfalfa were determined. The results showed that wilting significantly affected the contents of crude protein (CP),acid detergent fiber (ADF),ammonia nitrogen,and organic acid in alfalfa silage(P<0.05);The use of composite lactic acid bacteria under different water conditions can significantly increase the lactic acid content after silage (P<0.05),and reduce the content of acidic washing fiber,pH value,and ammonia nitrogen content (P<0.05);Adding composite lactic acid bacteria can improve the bacterial community structure of alfalfa silage. According to principal component analysis,under the condition of 59.43% moisture content in alfalfa,adding composite lactic acid bacteria for silage has the best effect and can effectively improve the quality of alfalfa silage. Adding molasses has the best effect when the moisture content of the raw material is 47.26%.

Key words: Alfalfa, Fermentation quality, Moisture, Compound lactic acid bacteria, Molasses

摘要： 本文旨在研究水分含量(67.69%，59.43%，47.26%和38.07%)对添加复合乳酸菌和2%糖蜜青贮后紫花苜蓿(Medicago sativa L.)青贮品质的影响。复合乳酸菌由植物乳杆菌和布氏乳杆菌组成，等比添加1×10⁷cfu·g^-1 FW。室温厌氧发酵后开袋对青贮苜蓿营养品质、发酵品质和微生物数量进行测定。结果表明，萎蔫对添加复合乳酸菌和糖蜜的苜蓿青贮后的粗蛋白(Crude protein，CP)、酸性洗涤纤维(Acid detergent fiber，ADF)、氨态氮和有机酸含量均有显著影响(P<0.05)；在不同水分条件下使用复合乳酸菌均能显著提高青贮后的乳酸含量(P<0.05)，降低酸性洗涤纤维含量、pH值和氨态氮含量(P<0.05)；添加复合乳酸菌在一定程度上能改善苜蓿青贮的细菌群落结构。根据主成分分析得出，苜蓿在含水量为59.43%条件下，添加复合乳酸菌青贮效果最佳，可有效提高青贮苜蓿品质。原料含水量为47.26%时添加糖蜜效果最佳。

关键词: 紫花苜蓿, 发酵品质, 水分, 复合乳酸菌, 糖蜜