甲酸添加剂及青贮时间对紫花苜蓿青贮品质的影响

以第2茬初花期(10%植株开花)刈割的紫花苜蓿为原料进行青贮,针对甲酸添加剂和青贮时间设计两因素试验,甲酸添加剂浓度为3(A₁)、6(A₂)和9 mL·kg^-1(A₃),以不添加作为对照(CK),分别在发酵30、60和120 d开袋分析。结果表明,适量的甲酸添加剂和适当的青贮时间能够改善青贮品质,甲酸添加剂能够显著降低青贮的pH、氨态氮/总氮及酸性洗涤纤维(ADF)值(P<0.05);除粗蛋白(CP)外,青贮时间对青贮原料的其他营养品质均有显著影响(P<0.05),在所有处理中,甲酸添加剂浓度6 mL·kg^-1(A₂),青贮时间60 d,苜蓿青贮效果最佳;甲酸添加剂和青贮时间的交互作用显著影响了干物质(DM)、中性洗涤纤维(NDF)和粗脂肪(EE)含量(P<0.05),对其他成分无显著影响(P>0.05)。

Effects of formic acid additives and ensiling time on the quality of alfalfa silage

In this study a second cut alfalfa crop harvested at the early flowering stage (10% of plants flowering) was used as raw material for making bagged silage. The research comprised a two-factor evaluation of formic acid as an additive [concentration 3 (A₁), 6 (A₂) or 9 mL·kg^-1 (A₃)], with no addition as the control. Silage bags from the various formic acid treatments were opened for fermentation analysis after 30, 60 and 120 days. Both formic acid addition and ensiling time significantly influenced silage quality. Formic acid addition significantly reduced the pH value, ammonia nitrogen:total nitrogen ratio, and acid detergent fiber (ADF) value of the silage (P<0.05). Except for crude protein (CP), silage time had a significant effect on the silage nutritional quality (P<0.05). Among all the treatments, alfalfa silage with 6 mL·kg^-1 formic acid added (A₂) and 60 days fermentation time gave the best overall result. The interaction effect between formic acid addition and ensiling time was significant for dry matter (DM), neutral detergent fiber (NDF) and crude fat (EE) content (P<0.05), but was not significant for other silage quality parameters (P>0.05).