青贮密度和青贮时间对紫花苜蓿发酵品质及营养成分的影响

Effects of Ensiling Density and Time on the Fermentation Quality and Nutrient Composition of Alfalfa Silage

为研究不同青贮密度和青贮时间对紫花苜蓿(Medicago sativa L.)发酵品质及营养成分的影响,本试验以第二茬初花期(10%植株开花)刈割的紫花苜蓿为原料,采用双因素试验设计,分别设计青贮密度550,600和650 kg·m^(-3)以及时间30,60和120d,对不同处理青贮料的发酵品质和营养成分进行分析。结果表明:除乙酸和粗蛋白(Crude protein,CP)含量外,青贮密度和时间的交互作用显著影响了苜蓿的发酵品质和营养成分(P<0.05);与密度为650kg·m^(-3)的处理组相比,密度为600kg·m^(-3)的处理组青贮30和60d后,乳酸和干物质(Dry matter,DM)含量增加,酸性洗涤纤维(Acid detergent fiber,ADF)和可溶性碳水化合物(Water soluble carbohydrate,WSC)含量减少;在密度为600kg·m^(-3)下,与青贮30d相比,青贮60d的样品中乳酸、乙酸、DM,CP和粗脂肪(Ether extract,EE)含量增加。综上,苜蓿在青贮密度600kg·m^(-3)、时间60d条件下,青贮效果最佳。

The second cut alfalfa(10%of the plants flowering)was used to make silage with different ensiling densities and times to explore its effect on nutrient composition and fermentation quality of silage.The ensiling density was 550,600,and 650kg·m^(-3),respectively;and the ensiling time was 30,60,120d,respectively.The results showed that the interaction of ensiling density and time significantly affected the fermentation quality and nutrient composition of alfalfa(P<0.05),except for acetic acid and crude protein(CP).Compared with the treatment group with a density of 650kg·m^(-3),the content of lactic acid and dry matter(DM)increased,and the contents of acid detergent fiber(ADF)and soluble carbohydrate(WSC)decreased in the treatment group with a density of 600kg·m^(-3)after 30and 60days of silage.At a density of 600kg·m^(-3),the contents of lactic acid,acetic acid,DM,CP and crude fat(EE)increased in the samples silaged for 60dcompared with 30d.Therefore,when the ensiling density was 600kg·m^(-3)and the ensiling time was 60days,the quality of alfalfa silage was the best.