不同类型青贮覆盖膜的性能研究及对青贮玉米品质的影响

Study on the properties of different silage film and its effect on the quality of silage maize

试验针对目前牧场青贮压窖过程中覆盖塑料薄膜的情形,以普通聚乙烯薄膜(S1)为对照例,研究探索添加尼龙高阻隔材料,中间层尼龙青贮覆盖膜(S2)、内层尼龙二合一青贮覆盖膜(S3)的机械性能、氧气阻隔性能,用于覆盖青贮玉米,对发酵品质及有氧稳定时间等指标进行测试,对经济实用性进行对比分析。结果显示:与S1相比,S3的拉伸强度、落镖冲击强度分别显著提高30.3%、26.9%(P<0.05),断裂伸长率降低45.5%(P<0.05),阻氧能力极显著提高约20倍(P<0.01);窖贮150 d后对不同顶层距离的青贮玉米进行取样检测,发现不同覆盖膜下顶层0~50 cm深度的指标值差异显著,S3覆盖下青贮玉米的干物质、水溶性碳水化合物含量分别比S1显著高6.7%~13.5%和25.0%~61.7%(P<0.05),S3覆盖下青贮玉米的灰分、干物质损失分别比S1显著低14.2%~16.8%和33.2%~34.4%(P<0.05),S3覆盖下的青贮玉米的pH值、乙酸含量及微生物数量显著低于S1(P<0.05),乳酸含量高25.9%~36.9%(P<0.05),有氧稳定时间提高2倍以上。研究表明,选用二合一高阻隔青贮覆盖膜有利于提高顶层窖贮玉米的品质,经济效益最佳。

In view of the current situation of covering plastic film in the process of silage making in pastures,taking ordinary polyethylene film(S1)as the comparative example,the mechanical properties and oxygen barrier properties of adding nylon high barrier material,middle layer nylon silage film(S2)and inner layer nylon 2 in 1 silage film(S3)were studied,which were used to cover corn silage.The fermentation quality and aerobic stability time were tested,and the economic practicability was compared and analyzed.The results showed that compared with S1,the tensile strength and dart impact strength of S3 were significantly increased by 30.3%and 26.9%(P<0.05),respectively,the elongation at break was decreased by 45.5%(P<0.05),and the oxygen barrier ability was extremely increased by nearly 20 times(P<0.01).After 150 d of storage in cellar,the silage corn with different top layer distances was sampled and tested,and it was found that the index values of the top layer 0~50 cm depth under different mulching films were significantly different,the contents of DM and water-soluble carbohydrates in silage maize under S3 coverage were significantly higher than those of S1 by 6.7%~13.5%and 25.0%~61.7%(P<0.05).Ash and dry matter losses in S3 were significantly lower than those in S1by 14.2%~16.8%and 33.2%~34.4%(P<0.05),pH value,acetic acid content and microbial count of silage maize covered by S3 were significantly lower than those of S1(P<0.05),the lactic acid content was 25.9%~36.9%higher(P<0.05),and the aerobic stabilization time was increased by more than two times.The experiment indicates that the 2 in 1 oxygen barrier silage film is beneficial to improve the quality of top layer corn silage,and the economic benefit is the best.